diff --git a/gui/src/app/App.tsx b/gui/src/app/App.tsx
index 67a3efa9..a068ad44 100644
--- a/gui/src/app/App.tsx
+++ b/gui/src/app/App.tsx
@@ -4,6 +4,7 @@ import ProjectContextProvider from "@SpCore/ProjectContextProvider";
 import HomePage from "@SpPages/HomePage";
 import { Analytics } from "@vercel/analytics/react";
 import { BrowserRouter } from "react-router-dom";
+import { CompileContextProvider } from "./CompileContext/CompileContextProvider";
 
 const theme = createTheme();
 
@@ -13,7 +14,9 @@ function App() {
       <ThemeProvider theme={theme}>
         <div className="MainWindow">
           <ProjectContextProvider>
-            <HomePage />
+            <CompileContextProvider>
+              <HomePage />
+            </CompileContextProvider>
           </ProjectContextProvider>
           <Analytics />
         </div>
diff --git a/gui/src/app/CompilationServerConnectionControl/CompilationServerConnectionControl.tsx b/gui/src/app/CompilationServerConnectionControl/CompilationServerConnectionControl.tsx
index f1a2620d..3ff84156 100644
--- a/gui/src/app/CompilationServerConnectionControl/CompilationServerConnectionControl.tsx
+++ b/gui/src/app/CompilationServerConnectionControl/CompilationServerConnectionControl.tsx
@@ -3,15 +3,22 @@ import { Cancel, Check } from "@mui/icons-material";
 import CloseableDialog, {
   useDialogControls,
 } from "@SpComponents/CloseableDialog";
-import { FunctionComponent, useCallback, useEffect, useState } from "react";
+import {
+  FunctionComponent,
+  useCallback,
+  useContext,
+  useEffect,
+  useState,
+} from "react";
 import ConfigureCompilationServerDialog from "./ConfigureCompilationServerDialog";
 import IconButton from "@mui/material/IconButton";
 import Typography from "@mui/material/Typography";
+import { CompileContext } from "@SpCompileContext/CompileContext";
 
 export const publicUrl = "https://trom-stan-wasm-server.magland.org";
 export const localUrl = "http://localhost:8083";
 
-export type ServerType = "public" | "local" | "custom";
+type ServerType = "public" | "local" | "custom";
 
 type CompilationServerConnectionControlProps = {
   // none
@@ -20,22 +27,8 @@ type CompilationServerConnectionControlProps = {
 const CompilationServerConnectionControl: FunctionComponent<
   CompilationServerConnectionControlProps
 > = () => {
-  const [stanWasmServerUrl, setStanWasmServerUrl] = useState<string>(
-    localStorage.getItem("stanWasmServerUrl") || publicUrl,
-  );
-
-  const [serverType, setServerType] = useState<ServerType>(
-    stanWasmServerUrl === publicUrl
-      ? "public"
-      : stanWasmServerUrl === localUrl
-        ? "local"
-        : "custom",
-  );
-
+  const { stanWasmServerUrl } = useContext(CompileContext);
   const { isConnected, retryConnection } = useIsConnected(stanWasmServerUrl);
-  useEffect(() => {
-    localStorage.setItem("stanWasmServerUrl", stanWasmServerUrl);
-  }, [stanWasmServerUrl]);
 
   const {
     handleOpen: openDialog,
@@ -47,6 +40,8 @@ const CompilationServerConnectionControl: FunctionComponent<
     retryConnection();
   }, [retryConnection]);
 
+  const serverType = serverTypeForUrl(stanWasmServerUrl);
+
   return (
     <>
       <IconButton onClick={openDialog} color="inherit" size="small">
@@ -68,18 +63,18 @@ const CompilationServerConnectionControl: FunctionComponent<
         handleClose={closeDialog}
       >
         <ConfigureCompilationServerDialog
-          stanWasmServerUrl={stanWasmServerUrl}
-          setStanWasmServerUrl={setStanWasmServerUrl}
           isConnected={isConnected}
           onRetry={handleRetry}
-          choice={serverType}
-          setChoice={setServerType}
         />
       </CloseableDialog>
     </>
   );
 };
 
+export const serverTypeForUrl = (url: string): ServerType => {
+  return url === publicUrl ? "public" : url === localUrl ? "local" : "custom";
+};
+
 const useIsConnected = (stanWasmServerUrl: string) => {
   const probeUrl = `${stanWasmServerUrl}/probe`;
   const [isConnected, setIsConnected] = useState<boolean>(false);
@@ -89,6 +84,11 @@ const useIsConnected = (stanWasmServerUrl: string) => {
   }, []);
   useEffect(() => {
     setIsConnected(false);
+    if (!probeUrl.startsWith("http://") && !probeUrl.startsWith("https://")) {
+      // important to do this check because otherwise fetch may succeed because
+      // the server of this web app may respond with success
+      return;
+    }
     (async () => {
       try {
         const response = await fetch(probeUrl);
diff --git a/gui/src/app/CompilationServerConnectionControl/ConfigureCompilationServerDialog.tsx b/gui/src/app/CompilationServerConnectionControl/ConfigureCompilationServerDialog.tsx
index a170bb13..095cbafa 100644
--- a/gui/src/app/CompilationServerConnectionControl/ConfigureCompilationServerDialog.tsx
+++ b/gui/src/app/CompilationServerConnectionControl/ConfigureCompilationServerDialog.tsx
@@ -1,38 +1,33 @@
-import { FunctionComponent, useCallback } from "react";
-import {
-  localUrl,
-  publicUrl,
-  ServerType,
-} from "./CompilationServerConnectionControl";
-import FormControl from "@mui/material/FormControl";
+import { CompileContext } from "@SpCompileContext/CompileContext";
+import { Refresh } from "@mui/icons-material";
 import Divider from "@mui/material/Divider";
-import FormLabel from "@mui/material/FormLabel";
-import RadioGroup from "@mui/material/RadioGroup";
+import FormControl from "@mui/material/FormControl";
 import FormControlLabel from "@mui/material/FormControlLabel";
+import FormLabel from "@mui/material/FormLabel";
+import IconButton from "@mui/material/IconButton";
 import Radio from "@mui/material/Radio";
+import RadioGroup from "@mui/material/RadioGroup";
 import TextField from "@mui/material/TextField";
-import IconButton from "@mui/material/IconButton";
-import { Refresh } from "@mui/icons-material";
+import { FunctionComponent, useCallback, useContext } from "react";
+import {
+  localUrl,
+  publicUrl,
+  serverTypeForUrl,
+} from "./CompilationServerConnectionControl";
 
 type ConfigureCompilationServerDialogProps = {
-  stanWasmServerUrl: string;
-  setStanWasmServerUrl: (url: string) => void;
   isConnected: boolean;
   onRetry: () => void;
-  choice: ServerType;
-  setChoice: (choice: ServerType) => void;
 };
 
 const ConfigureCompilationServerDialog: FunctionComponent<
   ConfigureCompilationServerDialogProps
-> = ({
-  stanWasmServerUrl,
-  setStanWasmServerUrl,
-  isConnected,
-  onRetry,
-  choice,
-  setChoice,
-}) => {
+> = ({ isConnected, onRetry }) => {
+  const { stanWasmServerUrl, setStanWasmServerUrl } =
+    useContext(CompileContext);
+
+  const serverType = serverTypeForUrl(stanWasmServerUrl);
+
   const makeChoice = useCallback(
     (_: unknown, choice: string) => {
       if (choice === "public") {
@@ -44,9 +39,8 @@ const ConfigureCompilationServerDialog: FunctionComponent<
       } else {
         return;
       }
-      setChoice(choice);
     },
-    [setChoice, setStanWasmServerUrl],
+    [setStanWasmServerUrl],
   );
 
   return (
@@ -73,7 +67,7 @@ const ConfigureCompilationServerDialog: FunctionComponent<
         <FormLabel id="compilation-server-selection">
           Compilation server
         </FormLabel>
-        <RadioGroup value={choice} onChange={makeChoice}>
+        <RadioGroup value={serverType} onChange={makeChoice}>
           <FormControlLabel
             value="public"
             control={<Radio />}
@@ -91,13 +85,13 @@ const ConfigureCompilationServerDialog: FunctionComponent<
           />
         </RadioGroup>
 
-        {choice === "custom" && (
+        {serverType === "custom" && (
           <div>
             <p>
               <TextField
                 variant="standard"
                 label="Custom server URL"
-                disabled={choice !== "custom"}
+                disabled={serverType !== "custom"}
                 value={stanWasmServerUrl}
                 onChange={(e) => setStanWasmServerUrl(e.target.value)}
               />
@@ -106,7 +100,7 @@ const ConfigureCompilationServerDialog: FunctionComponent<
         )}
       </FormControl>
 
-      {choice === "local" && (
+      {serverType === "local" && (
         <div>
           <p>
             To start a local compilation server{" "}
@@ -119,7 +113,7 @@ const ConfigureCompilationServerDialog: FunctionComponent<
           </div>
         </div>
       )}
-      {choice === "public" && (
+      {serverType === "public" && (
         <div>
           <p>
             The public server <span className="details">({publicUrl})</span> is
diff --git a/gui/src/app/CompileContext/CompileContext.ts b/gui/src/app/CompileContext/CompileContext.ts
new file mode 100644
index 00000000..cfd9d01e
--- /dev/null
+++ b/gui/src/app/CompileContext/CompileContext.ts
@@ -0,0 +1,29 @@
+import { createContext } from "react";
+
+export type CompileStatus =
+  | "preparing"
+  | "compiling"
+  | "compiled"
+  | "failed"
+  | "";
+
+type CompileContextType = {
+  compileStatus: CompileStatus;
+  compileMessage: string;
+  compiledMainJsUrl?: string;
+  validSyntax: boolean;
+  compile: () => void;
+  setValidSyntax: (valid: boolean) => void;
+  stanWasmServerUrl: string;
+  setStanWasmServerUrl: (url: string) => void;
+};
+
+export const CompileContext = createContext<CompileContextType>({
+  compileStatus: "",
+  compileMessage: "",
+  validSyntax: false,
+  compile: () => {},
+  setValidSyntax: () => {},
+  stanWasmServerUrl: "",
+  setStanWasmServerUrl: () => {},
+});
diff --git a/gui/src/app/CompileContext/CompileContextProvider.tsx b/gui/src/app/CompileContext/CompileContextProvider.tsx
new file mode 100644
index 00000000..5f2c5d04
--- /dev/null
+++ b/gui/src/app/CompileContext/CompileContextProvider.tsx
@@ -0,0 +1,102 @@
+import { ProjectContext } from "@SpCore/ProjectContextProvider";
+import compileStanProgram from "@SpCompileContext/compileStanProgram";
+import {
+  FunctionComponent,
+  PropsWithChildren,
+  useCallback,
+  useContext,
+  useEffect,
+  useState,
+} from "react";
+import { CompileContext, CompileStatus } from "./CompileContext";
+
+type CompileContextProviderProps = {
+  // none
+};
+
+const initialStanWasmServerUrl =
+  localStorage.getItem("stanWasmServerUrl") ||
+  "https://trom-stan-wasm-server.magland.org";
+
+export const CompileContextProvider: FunctionComponent<
+  PropsWithChildren<CompileContextProviderProps>
+> = ({ children }) => {
+  const { data } = useContext(ProjectContext);
+  const [compileStatus, setCompileStatus] = useState<CompileStatus>("");
+  const [
+    theStanFileContentThasHasBeenCompiled,
+    setTheStanFileContentThasHasBeenCompiled,
+  ] = useState<string>("");
+  const [compileMessage, setCompileMessage] = useState<string>("");
+  const [compiledMainJsUrl, setCompiledMainJsUrl] = useState<
+    string | undefined
+  >(undefined);
+  const [validSyntax, setValidSyntax] = useState<boolean>(false);
+
+  useEffect(() => {
+    // if the compiled content is not the same as the current content,
+    // then the state should not be compiled or failed
+    if (data.stanFileContent !== theStanFileContentThasHasBeenCompiled) {
+      if (compileStatus === "compiled" || compileStatus === "failed") {
+        setCompileStatus("");
+        setCompiledMainJsUrl("");
+      }
+    }
+  }, [
+    data.stanFileContent,
+    theStanFileContentThasHasBeenCompiled,
+    compileStatus,
+    setCompiledMainJsUrl,
+  ]);
+
+  const [stanWasmServerUrl, setStanWasmServerUrl] = useState<string>(
+    initialStanWasmServerUrl,
+  );
+  useEffect(() => {
+    // persist to local storage
+    localStorage.setItem("stanWasmServerUrl", stanWasmServerUrl);
+  }, [stanWasmServerUrl]);
+
+  const handleCompile = useCallback(async () => {
+    setCompileStatus("compiling");
+    await new Promise((resolve) => setTimeout(resolve, 500)); // for effect
+    const onStatus = (msg: string) => {
+      setCompileMessage(msg);
+    };
+    const { mainJsUrl } = await compileStanProgram(
+      stanWasmServerUrl,
+      data.stanFileContent,
+      onStatus,
+    );
+
+    if (!mainJsUrl) {
+      setCompileStatus("failed");
+      return;
+    }
+    setCompiledMainJsUrl(mainJsUrl);
+    setCompileStatus("compiled");
+    setTheStanFileContentThasHasBeenCompiled(data.stanFileContent);
+  }, [
+    data.stanFileContent,
+    setCompiledMainJsUrl,
+    setCompileStatus,
+    stanWasmServerUrl,
+  ]);
+
+  return (
+    <CompileContext.Provider
+      value={{
+        compileStatus,
+        compileMessage,
+        compiledMainJsUrl,
+        validSyntax,
+        compile: handleCompile,
+        setValidSyntax,
+        stanWasmServerUrl,
+        setStanWasmServerUrl,
+      }}
+    >
+      {children}
+    </CompileContext.Provider>
+  );
+};
diff --git a/gui/src/app/compileStanProgram/compileStanProgram.ts b/gui/src/app/CompileContext/compileStanProgram.ts
similarity index 100%
rename from gui/src/app/compileStanProgram/compileStanProgram.ts
rename to gui/src/app/CompileContext/compileStanProgram.ts
diff --git a/gui/src/app/compileStanProgram/mainJsUrlCache.ts b/gui/src/app/CompileContext/mainJsUrlCache.ts
similarity index 100%
rename from gui/src/app/compileStanProgram/mainJsUrlCache.ts
rename to gui/src/app/CompileContext/mainJsUrlCache.ts
diff --git a/gui/src/app/FileEditor/StanFileEditor.tsx b/gui/src/app/FileEditor/StanFileEditor.tsx
index 670053be..d49a925c 100644
--- a/gui/src/app/FileEditor/StanFileEditor.tsx
+++ b/gui/src/app/FileEditor/StanFileEditor.tsx
@@ -3,12 +3,12 @@ import { AutoFixHigh, Cancel, Help, Settings } from "@mui/icons-material";
 import StanCompileResultWindow from "@SpComponents/StanCompileResultWindow";
 import TextEditor from "@SpComponents/TextEditor";
 import { ToolbarItem } from "@SpComponents/ToolBar";
-import compileStanProgram from "@SpStanc/compileStanProgram";
 import { stancErrorsToCodeMarkers } from "@SpStanc/Linting";
 import useStanc from "@SpStanc/useStanc";
+import { CompileContext } from "@SpCompileContext/CompileContext";
 import {
   FunctionComponent,
-  useCallback,
+  useContext,
   useEffect,
   useMemo,
   useState,
@@ -22,11 +22,8 @@ type Props = {
   setEditedFileContent: (text: string) => void;
   onDeleteFile?: () => void;
   readOnly: boolean;
-  setCompiledUrl: (s: string) => void;
 };
 
-type CompileStatus = "preparing" | "compiling" | "compiled" | "failed" | "";
-
 const StanFileEditor: FunctionComponent<Props> = ({
   fileName,
   fileContent,
@@ -34,7 +31,6 @@ const StanFileEditor: FunctionComponent<Props> = ({
   editedFileContent,
   setEditedFileContent,
   readOnly,
-  setCompiledUrl,
 }) => {
   const { stancErrors, requestFormat } = useStanc(
     "main.stan",
@@ -42,61 +38,21 @@ const StanFileEditor: FunctionComponent<Props> = ({
     setEditedFileContent,
   );
 
+  const { compileStatus, compileMessage, compile, setValidSyntax } =
+    useContext(CompileContext);
+
   const validSyntax = useMemo(() => {
     return stancErrors.errors === undefined;
   }, [stancErrors]);
 
+  useEffect(() => {
+    setValidSyntax(validSyntax);
+  }, [validSyntax, setValidSyntax]);
+
   const hasWarnings = useMemo(() => {
     return stancErrors.warnings && stancErrors.warnings.length > 0;
   }, [stancErrors]);
 
-  const [compileStatus, setCompileStatus] = useState<CompileStatus>("");
-  const [
-    theStanFileContentThasHasBeenCompiled,
-    setTheStanFileContentThasHasBeenCompiled,
-  ] = useState<string>("");
-  const [compileMessage, setCompileMessage] = useState<string>("");
-
-  const handleCompile = useCallback(async () => {
-    setCompileStatus("compiling");
-    await new Promise((resolve) => setTimeout(resolve, 500)); // for effect
-    const onStatus = (msg: string) => {
-      setCompileMessage(msg);
-    };
-    const stanWasmServerUrl =
-      localStorage.getItem("stanWasmServerUrl") ||
-      "https://trom-stan-wasm-server.magland.org";
-    const { mainJsUrl } = await compileStanProgram(
-      stanWasmServerUrl,
-      fileContent,
-      onStatus,
-    );
-
-    if (!mainJsUrl) {
-      setCompileStatus("failed");
-      return;
-    }
-    setCompiledUrl(mainJsUrl);
-    setCompileStatus("compiled");
-    setTheStanFileContentThasHasBeenCompiled(fileContent);
-  }, [fileContent, setCompiledUrl]);
-
-  useEffect(() => {
-    // if the compiled content is not the same as the current content,
-    // then the state should not be compiled or failed
-    if (fileContent !== theStanFileContentThasHasBeenCompiled) {
-      if (compileStatus === "compiled" || compileStatus === "failed") {
-        setCompileStatus("");
-        setCompiledUrl("");
-      }
-    }
-  }, [
-    fileContent,
-    theStanFileContentThasHasBeenCompiled,
-    compileStatus,
-    setCompiledUrl,
-  ]);
-
   const [syntaxWindowVisible, setSyntaxWindowVisible] = useState(false);
 
   const toolbarItems: ToolbarItem[] = useMemo(() => {
@@ -154,7 +110,7 @@ const StanFileEditor: FunctionComponent<Props> = ({
             tooltip: "Compile Stan model",
             label: "Compile",
             icon: <Settings />,
-            onClick: handleCompile,
+            onClick: compile,
             color: "darkblue",
           });
         }
@@ -178,7 +134,7 @@ const StanFileEditor: FunctionComponent<Props> = ({
   }, [
     editedFileContent,
     fileContent,
-    handleCompile,
+    compile,
     requestFormat,
     validSyntax,
     compileStatus,
diff --git a/gui/src/app/RunPanel/CompiledRunPanel.tsx b/gui/src/app/RunPanel/CompiledRunPanel.tsx
new file mode 100644
index 00000000..167ed641
--- /dev/null
+++ b/gui/src/app/RunPanel/CompiledRunPanel.tsx
@@ -0,0 +1,141 @@
+import Box from "@mui/material/Box";
+import LinearProgress, {
+  LinearProgressProps,
+} from "@mui/material/LinearProgress";
+import Typography from "@mui/material/Typography";
+import { FunctionComponent } from "react";
+
+import Button from "@mui/material/Button";
+import { SamplingOpts } from "@SpCore/ProjectDataModel";
+import { Progress } from "@SpStanSampler/StanModelWorker";
+import { StanSamplerStatus } from "@SpStanSampler/StanSampler";
+
+type CompiledRunPanelProps = {
+  handleRun: () => Promise<void>;
+  cancelRun: () => void;
+  runStatus: StanSamplerStatus;
+  progress: Progress | undefined;
+  samplingOpts: SamplingOpts;
+  errorMessage: string;
+};
+
+const loadingDiv = <div>Loading compiled Stan model...</div>;
+const completedDiv = <div>done sampling</div>;
+
+const CompiledRunPanel: FunctionComponent<CompiledRunPanelProps> = ({
+  handleRun,
+  runStatus,
+  cancelRun,
+  progress,
+  samplingOpts,
+  errorMessage,
+}) => {
+  const samplingDiv = (
+    <>
+      <Button
+        color="error"
+        variant="outlined"
+        onClick={cancelRun}
+        disabled={runStatus !== "sampling"}
+      >
+        cancel
+      </Button>
+      <div>
+        Sampling
+        <SamplingProgressComponent
+          report={progress}
+          numChains={samplingOpts.num_chains}
+        />
+      </div>
+    </>
+  );
+
+  const failedDiv = (
+    <div>
+      Sampling failed!
+      <pre className="SamplerError">{errorMessage}</pre>
+      <span className="details">(see browser console for more details)</span>
+    </div>
+  );
+
+  return (
+    <div>
+      <Button
+        variant="contained"
+        color="success"
+        onClick={handleRun}
+        disabled={runStatus === "sampling" || runStatus === "loading"}
+      >
+        run sampling
+      </Button>
+      &nbsp;
+      <hr />
+      {runStatus === "loading" ? (
+        loadingDiv
+      ) : runStatus === "completed" ? (
+        completedDiv
+      ) : runStatus === "failed" ? (
+        failedDiv
+      ) : runStatus === "sampling" ? (
+        samplingDiv
+      ) : (
+        <></>
+      )}
+    </div>
+  );
+};
+
+type SamplingProgressComponentProps = {
+  report: Progress | undefined;
+  numChains: number;
+};
+
+const SamplingProgressComponent: FunctionComponent<
+  SamplingProgressComponentProps
+> = ({ report, numChains }) => {
+  if (!report) return <span />;
+  const progress =
+    ((report.iteration + (report.chain - 1) * report.totalIterations) /
+      (report.totalIterations * numChains)) *
+    100;
+  return (
+    <>
+      <div className="SamplingProgress">
+        <LinearProgressWithLabel
+          sx={{
+            height: 10,
+            // https://stackoverflow.com/a/73009519
+            "& .MuiLinearProgress-bar": {
+              transition: "none",
+            },
+          }}
+          value={progress}
+        />
+      </div>
+      <div>
+        Chain {report.chain} Iteration: {report.iteration} /{" "}
+        {report.totalIterations} ({report.warmup ? "Warmup" : "Sampling"})
+      </div>
+    </>
+  );
+};
+
+// from https://mui.com/material-ui/react-progress/#linear-with-label
+const LinearProgressWithLabel = (
+  props: LinearProgressProps & { value: number },
+) => {
+  return (
+    <Box sx={{ display: "flex", alignItems: "center" }}>
+      <Box sx={{ width: "100%", mr: 1 }}>
+        <LinearProgress variant="determinate" {...props} />
+      </Box>
+      <Box sx={{ minWidth: 35 }}>
+        <Typography variant="body2" color="text.secondary">{`${Math.round(
+          props.value,
+        )}%`}</Typography>
+      </Box>
+    </Box>
+  );
+};
+
+export default CompiledRunPanel;
diff --git a/gui/src/app/RunPanel/RunPanel.tsx b/gui/src/app/RunPanel/RunPanel.tsx
index 8b2f18a5..dc2c6c56 100644
--- a/gui/src/app/RunPanel/RunPanel.tsx
+++ b/gui/src/app/RunPanel/RunPanel.tsx
@@ -1,16 +1,17 @@
 /* eslint-disable @typescript-eslint/no-explicit-any */
-import Box from "@mui/material/Box";
-import LinearProgress, {
-  LinearProgressProps,
-} from "@mui/material/LinearProgress";
-import Typography from "@mui/material/Typography";
-import { FunctionComponent, useCallback } from "react";
+import { FunctionComponent, useCallback, useContext } from "react";
 
-import { SamplingOpts } from "@SpCore/ProjectDataModel";
-import { Progress } from "@SpStanSampler/StanModelWorker";
+import Button from "@mui/material/Button";
+import { CompileContext } from "@SpCompileContext/CompileContext";
+import { ProjectContext } from "@SpCore/ProjectContextProvider";
+import {
+  ProjectDataModel,
+  SamplingOpts,
+  modelHasUnsavedChanges,
+} from "@SpCore/ProjectDataModel";
 import StanSampler from "@SpStanSampler/StanSampler";
 import { StanRun } from "@SpStanSampler/useStanSampler";
-import Button from "@mui/material/Button";
+import CompiledRunPanel from "./CompiledRunPanel";
 
 type RunPanelProps = {
   sampler?: StanSampler;
@@ -39,113 +40,59 @@ const RunPanel: FunctionComponent<RunPanelProps> = ({
     sampler.cancel();
   }, [sampler]);
 
-  if (!sampler)
-    return <div className="RunPanelPadded">Stan model not compiled</div>;
+  const { compile, compileMessage, compileStatus, validSyntax } =
+    useContext(CompileContext);
+
+  const { data: projectData } = useContext(ProjectContext);
 
   if (!dataIsSaved) {
     return <div className="RunPanelPadded">Data not saved</div>;
   }
-  return (
-    <div className="RunPanel">
-      <div className="RunPanelPadded">
-        <div>
-          <Button
-            variant="contained"
-            color="success"
-            onClick={handleRun}
-            disabled={runStatus === "sampling" || runStatus === "loading"}
-          >
-            run sampling
-          </Button>
-          &nbsp;
-          {runStatus === "sampling" && (
-            <Button
-              color="error"
-              variant="outlined"
-              onClick={cancelRun}
-              disabled={runStatus !== "sampling"}
-            >
-              cancel
-            </Button>
-          )}
-          <hr />
-          {runStatus === "loading" && <div>Loading compiled Stan model...</div>}
-          {runStatus === "sampling" && (
-            <div>
-              Sampling
-              <SamplingProgressComponent
-                report={progress}
-                numChains={samplingOpts.num_chains}
-              />
-            </div>
-          )}
-          {runStatus === "completed" && <div>done sampling</div>}
-          {runStatus === "failed" && (
-            <div>
-              Sampling failed!
-              <pre className="SamplerError">{errorMessage}</pre>
-              <span className="details">
-                (see browser console for more details)
-              </span>
-            </div>
-          )}
-        </div>
-      </div>
+
+  const compileDiv = (
+    <div>
+      <Button
+        variant="contained"
+        onClick={compile}
+        disabled={isCompileModelDisabled(projectData, validSyntax)}
+      >
+        compile model
+      </Button>
     </div>
   );
-};
 
-type SamplingProgressComponentProps = {
-  report: Progress | undefined;
-  numChains: number;
-};
+  const compilingDiv = <div>{compileMessage}</div>;
 
-const SamplingProgressComponent: FunctionComponent<
-  SamplingProgressComponentProps
-> = ({ report, numChains }) => {
-  if (!report) return <span />;
-  const progress =
-    ((report.iteration + (report.chain - 1) * report.totalIterations) /
-      (report.totalIterations * numChains)) *
-    100;
   return (
-    <>
-      <div className="SamplingProgress">
-        <LinearProgressWithLabel
-          sx={{
-            height: 10,
-            // https://stackoverflow.com/a/73009519
-            "& .MuiLinearProgress-bar": {
-              transition: "none",
-            },
-          }}
-          value={progress}
-        />
-      </div>
-      <div>
-        Chain {report.chain} Iteration: {report.iteration} /{" "}
-        {report.totalIterations} ({report.warmup ? "Warmup" : "Sampling"})
+    <div className="RunPanel">
+      <div className="RunPanelPadded">
+        {compileStatus === "compiled" ? (
+          <CompiledRunPanel
+            handleRun={handleRun}
+            cancelRun={cancelRun}
+            runStatus={runStatus}
+            progress={progress}
+            samplingOpts={samplingOpts}
+            errorMessage={errorMessage}
+          />
+        ) : ["preparing", "compiling"].includes(compileStatus) ? (
+          compilingDiv
+        ) : (
+          compileDiv
+        )}
       </div>
-    </>
+    </div>
   );
 };
 
-// from https://mui.com/material-ui/react-progress/#linear-with-label
-const LinearProgressWithLabel = (
-  props: LinearProgressProps & { value: number },
+const isCompileModelDisabled = (
+  projectData: ProjectDataModel,
+  validSyntax: boolean,
 ) => {
-  return (
-    <Box sx={{ display: "flex", alignItems: "center" }}>
-      <Box sx={{ width: "100%", mr: 1 }}>
-        <LinearProgress variant="determinate" {...props} />
-      </Box>
-      <Box sx={{ minWidth: 35 }}>
-        <Typography variant="body2" color="text.secondary">{`${Math.round(
-          props.value,
-        )}%`}</Typography>
-      </Box>
-    </Box>
-  );
+  if (!validSyntax) return true;
+  if (!projectData.stanFileContent.trim()) return true;
+  if (modelHasUnsavedChanges(projectData)) return true;
+  return false;
 };
 
 export default RunPanel;
diff --git a/gui/src/app/pages/HomePage/HomePage.tsx b/gui/src/app/pages/HomePage/HomePage.tsx
index 75042619..6e1ffa52 100644
--- a/gui/src/app/pages/HomePage/HomePage.tsx
+++ b/gui/src/app/pages/HomePage/HomePage.tsx
@@ -1,7 +1,11 @@
+import { Split } from "@geoffcox/react-splitter";
 import Box from "@mui/material/Box";
 import styled from "@mui/material/styles/styled";
 import useMediaQuery from "@mui/material/useMediaQuery";
 import StanFileEditor from "@SpComponents/StanFileEditor";
+import TabWidget from "@SpComponents/TabWidget";
+import TextEditor from "@SpComponents/TextEditor";
+import { FileNames } from "@SpCore/FileMapping";
 import { ProjectContext } from "@SpCore/ProjectContextProvider";
 import {
   modelHasUnsavedChanges,
@@ -9,6 +13,8 @@ import {
 } from "@SpCore/ProjectDataModel";
 import Sidebar, { drawerWidth } from "@SpPages/Sidebar";
 import TopBar from "@SpPages/TopBar";
+import DataPyWindow from "@SpScripting/DataGeneration/DataPyWindow";
+import DataRWindow from "@SpScripting/DataGeneration/DataRWindow";
 import {
   FunctionComponent,
   useContext,
@@ -16,13 +22,7 @@ import {
   useRef,
   useState,
 } from "react";
-import TabWidget from "@SpComponents/TabWidget";
 import SamplingWindow from "./SamplingWindow/SamplingWindow";
-import { FileNames } from "@SpCore/FileMapping";
-import DataRWindow from "@SpScripting/DataGeneration/DataRWindow";
-import DataPyWindow from "@SpScripting/DataGeneration/DataPyWindow";
-import TextEditor from "@SpComponents/TextEditor";
-import { Split } from "@geoffcox/react-splitter";
 
 type Props = {
   //
@@ -31,8 +31,6 @@ type Props = {
 const HomePage: FunctionComponent<Props> = () => {
   const { data } = useContext(ProjectContext);
 
-  const [compiledMainJsUrl, setCompiledMainJsUrl] = useState<string>("");
-
   const smallScreen = useMediaQuery("(max-width:600px)");
 
   const [leftPanelCollapsed, setLeftPanelCollapsed] = useState(smallScreen);
@@ -64,8 +62,8 @@ const HomePage: FunctionComponent<Props> = () => {
 
       <MovingBox open={leftPanelCollapsed} flex="1" minHeight="0">
         <Split minPrimarySize="80px" minSecondarySize="120px">
-          <LeftView setCompiledMainJsUrl={setCompiledMainJsUrl} />
-          <RightView compiledMainJsUrl={compiledMainJsUrl} />
+          <LeftView />
+          <RightView />
         </Split>
       </MovingBox>
     </Box>
@@ -73,15 +71,13 @@ const HomePage: FunctionComponent<Props> = () => {
 };
 
 type RightViewProps = {
-  compiledMainJsUrl: string;
+  // none
 };
 
-const RightView: FunctionComponent<RightViewProps> = ({
-  compiledMainJsUrl,
-}) => {
+const RightView: FunctionComponent<RightViewProps> = () => {
   return (
     <TabWidget labels={["Sampling", "Data Generation"]}>
-      <SamplingWindow compiledMainJsUrl={compiledMainJsUrl} />
+      <SamplingWindow />
       <TabWidget labels={["Python", "R"]}>
         <DataPyWindow />
         <DataRWindow />
@@ -91,12 +87,10 @@ const RightView: FunctionComponent<RightViewProps> = ({
 };
 
 type LeftViewProps = {
-  setCompiledMainJsUrl: (url: string) => void;
+  // none
 };
 
-const LeftView: FunctionComponent<LeftViewProps> = ({
-  setCompiledMainJsUrl,
-}) => {
+const LeftView: FunctionComponent<LeftViewProps> = () => {
   const { data, update } = useContext(ProjectContext);
   return (
     <Split horizontal>
@@ -119,7 +113,6 @@ const LeftView: FunctionComponent<LeftViewProps> = ({
           })
         }
         readOnly={false}
-        setCompiledUrl={setCompiledMainJsUrl}
       />
       <TextEditor
         language="json"
diff --git a/gui/src/app/pages/HomePage/SamplingWindow/SamplingWindow.tsx b/gui/src/app/pages/HomePage/SamplingWindow/SamplingWindow.tsx
index 23310e16..91d54b72 100644
--- a/gui/src/app/pages/HomePage/SamplingWindow/SamplingWindow.tsx
+++ b/gui/src/app/pages/HomePage/SamplingWindow/SamplingWindow.tsx
@@ -15,14 +15,13 @@ import {
 import AnalysisPyWindow from "@SpScripting/Analysis/AnalysisPyWindow";
 import useStanSampler, { StanRun } from "@SpStanSampler/useStanSampler";
 import AnalysisRWindow from "@SpScripting/Analysis/AnalysisRWindow";
+import { CompileContext } from "@SpCompileContext/CompileContext";
 
 type SamplingWindowProps = {
-  compiledMainJsUrl?: string;
+  // none
 };
 
-const SamplingWindow: FunctionComponent<SamplingWindowProps> = ({
-  compiledMainJsUrl,
-}) => {
+const SamplingWindow: FunctionComponent<SamplingWindowProps> = () => {
   const { data, update } = useContext(ProjectContext);
   const parsedData = useMemo(() => {
     try {
@@ -39,6 +38,8 @@ const SamplingWindow: FunctionComponent<SamplingWindowProps> = ({
     [update],
   );
 
+  const { compiledMainJsUrl } = useContext(CompileContext);
+
   const { sampler, latestRun } = useStanSampler(compiledMainJsUrl);
   const isSampling = latestRun.status === "sampling";
   return (
diff --git a/gui/tsconfig.json b/gui/tsconfig.json
index 765fbda1..a5db7f43 100644
--- a/gui/tsconfig.json
+++ b/gui/tsconfig.json
@@ -37,15 +37,12 @@
       "@SpCore/gists/*": ["app/gists/*"],
       /* We are playing a bit fast and loose with the distinction */
       "@SpPages/*": ["app/pages/HomePage/*"],
-      "@SpStanc/*": [
-        "app/Stanc/*",
-        "app/CompilationServerConnectionControl/*",
-        "app/compileStanProgram/*"
-      ],
+      "@SpStanc/*": ["app/Stanc/*", "app/CompilationServerConnectionControl/*"],
       "@SpStanSampler/*": ["app/StanSampler/*"],
       "@SpUtil/*": ["app/util/*"],
       "@SpStanStats/*": ["app/util/stan_stats/*"],
-      "@SpScripting/*": ["app/Scripting/*"]
+      "@SpScripting/*": ["app/Scripting/*"],
+      "@SpCompileContext/*": ["app/CompileContext/*"]
     }
   },
   "include": ["src", "test"],