diff --git a/bower.json b/bower.json
index dca71fb3..337cd0b5 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "aurelia-templating",
-  "version": "1.5.0",
+  "version": "1.6.0",
   "description": "An extensible HTML templating engine supporting databinding, custom elements, attached behaviors and more.",
   "keywords": [
     "aurelia",
diff --git a/dist/amd/aurelia-templating.js b/dist/amd/aurelia-templating.js
index 10a9554b..797f5b5f 100644
--- a/dist/amd/aurelia-templating.js
+++ b/dist/amd/aurelia-templating.js
@@ -2828,6 +2828,8 @@ define(['exports', 'aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aureli
         auTargetID = makeIntoInstructionTarget(node);
         instructions[auTargetID] = TargetInstruction.lifting(parentInjectorId, liftingInstruction);
       } else {
+        var skipContentProcessing = false;
+
         if (expressions.length || behaviorInstructions.length) {
           injectorId = behaviorInstructions.length ? getNextInjectorId() : false;
 
@@ -2835,6 +2837,7 @@ define(['exports', 'aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aureli
             instruction = behaviorInstructions[i];
             instruction.type.compile(this, resources, node, instruction, parentNode);
             providers.push(instruction.type.target);
+            skipContentProcessing = skipContentProcessing || instruction.skipContentProcessing;
           }
 
           for (i = 0, ii = expressions.length; i < ii; ++i) {
@@ -2848,7 +2851,7 @@ define(['exports', 'aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aureli
           instructions[auTargetID] = TargetInstruction.normal(injectorId, parentInjectorId, providers, behaviorInstructions, expressions, elementInstruction);
         }
 
-        if (elementInstruction && elementInstruction.skipContentProcessing) {
+        if (skipContentProcessing) {
           return node.nextSibling;
         }
 
@@ -3167,6 +3170,8 @@ define(['exports', 'aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aureli
     return ProxyViewFactory;
   }();
 
+  var auSlotBehavior = null;
+
   var ViewEngine = exports.ViewEngine = (_dec8 = (0, _aureliaDependencyInjection.inject)(_aureliaLoader.Loader, _aureliaDependencyInjection.Container, ViewCompiler, ModuleAnalyzer, ViewResources), _dec8(_class14 = (_temp4 = _class15 = function () {
     function ViewEngine(loader, container, viewCompiler, moduleAnalyzer, appResources) {
       
@@ -3178,8 +3183,12 @@ define(['exports', 'aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aureli
       this.appResources = appResources;
       this._pluginMap = {};
 
-      var auSlotBehavior = new HtmlBehaviorResource();
-      auSlotBehavior.attributeName = 'au-slot';
+      if (auSlotBehavior === null) {
+        auSlotBehavior = new HtmlBehaviorResource();
+        auSlotBehavior.attributeName = 'au-slot';
+        _aureliaMetadata.metadata.define(_aureliaMetadata.metadata.resource, auSlotBehavior, SlotCustomAttribute);
+      }
+
       auSlotBehavior.initialize(container, SlotCustomAttribute);
       auSlotBehavior.register(appResources);
     }
@@ -4046,6 +4055,8 @@ define(['exports', 'aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aureli
         } else {
           instruction.skipContentProcessing = true;
         }
+      } else if (!this.processContent(compiler, resources, node, instruction)) {
+        instruction.skipContentProcessing = true;
       }
 
       return node;
diff --git a/dist/aurelia-templating.js b/dist/aurelia-templating.js
index 969057c9..ede0f512 100644
--- a/dist/aurelia-templating.js
+++ b/dist/aurelia-templating.js
@@ -3528,6 +3528,8 @@ export class ViewCompiler {
       auTargetID = makeIntoInstructionTarget(node);
       instructions[auTargetID] = TargetInstruction.lifting(parentInjectorId, liftingInstruction);
     } else {
+      let skipContentProcessing = false;
+
       if (expressions.length || behaviorInstructions.length) {
         injectorId = behaviorInstructions.length ? getNextInjectorId() : false;
 
@@ -3535,6 +3537,7 @@ export class ViewCompiler {
           instruction = behaviorInstructions[i];
           instruction.type.compile(this, resources, node, instruction, parentNode);
           providers.push(instruction.type.target);
+          skipContentProcessing = skipContentProcessing || instruction.skipContentProcessing;
         }
 
         for (i = 0, ii = expressions.length; i < ii; ++i) {
@@ -3555,7 +3558,7 @@ export class ViewCompiler {
         );
       }
 
-      if (elementInstruction && elementInstruction.skipContentProcessing) {
+      if (skipContentProcessing) {
         return node.nextSibling;
       }
 
@@ -3921,6 +3924,8 @@ class ProxyViewFactory {
   }
 }
 
+let auSlotBehavior = null;
+
 /**
 * Controls the view resource loading pipeline.
 */
@@ -3947,8 +3952,12 @@ export class ViewEngine {
     this.appResources = appResources;
     this._pluginMap = {};
 
-    let auSlotBehavior = new HtmlBehaviorResource();
-    auSlotBehavior.attributeName = 'au-slot';
+    if (auSlotBehavior === null) {
+      auSlotBehavior  = new HtmlBehaviorResource();
+      auSlotBehavior.attributeName = 'au-slot';
+      metadata.define(metadata.resource, auSlotBehavior, SlotCustomAttribute);
+    }
+
     auSlotBehavior.initialize(container, SlotCustomAttribute);
     auSlotBehavior.register(appResources);
   }
@@ -4989,6 +4998,8 @@ export class HtmlBehaviorResource {
       } else {
         instruction.skipContentProcessing = true;
       }
+    } else if (!this.processContent(compiler, resources, node, instruction)) {
+      instruction.skipContentProcessing = true;
     }
 
     return node;
diff --git a/dist/commonjs/aurelia-templating.js b/dist/commonjs/aurelia-templating.js
index 8b220dd6..6a0c0716 100644
--- a/dist/commonjs/aurelia-templating.js
+++ b/dist/commonjs/aurelia-templating.js
@@ -2809,6 +2809,8 @@ var ViewCompiler = exports.ViewCompiler = (_dec7 = (0, _aureliaDependencyInjecti
       auTargetID = makeIntoInstructionTarget(node);
       instructions[auTargetID] = TargetInstruction.lifting(parentInjectorId, liftingInstruction);
     } else {
+      var skipContentProcessing = false;
+
       if (expressions.length || behaviorInstructions.length) {
         injectorId = behaviorInstructions.length ? getNextInjectorId() : false;
 
@@ -2816,6 +2818,7 @@ var ViewCompiler = exports.ViewCompiler = (_dec7 = (0, _aureliaDependencyInjecti
           instruction = behaviorInstructions[i];
           instruction.type.compile(this, resources, node, instruction, parentNode);
           providers.push(instruction.type.target);
+          skipContentProcessing = skipContentProcessing || instruction.skipContentProcessing;
         }
 
         for (i = 0, ii = expressions.length; i < ii; ++i) {
@@ -2829,7 +2832,7 @@ var ViewCompiler = exports.ViewCompiler = (_dec7 = (0, _aureliaDependencyInjecti
         instructions[auTargetID] = TargetInstruction.normal(injectorId, parentInjectorId, providers, behaviorInstructions, expressions, elementInstruction);
       }
 
-      if (elementInstruction && elementInstruction.skipContentProcessing) {
+      if (skipContentProcessing) {
         return node.nextSibling;
       }
 
@@ -3148,6 +3151,8 @@ var ProxyViewFactory = function () {
   return ProxyViewFactory;
 }();
 
+var auSlotBehavior = null;
+
 var ViewEngine = exports.ViewEngine = (_dec8 = (0, _aureliaDependencyInjection.inject)(_aureliaLoader.Loader, _aureliaDependencyInjection.Container, ViewCompiler, ModuleAnalyzer, ViewResources), _dec8(_class14 = (_temp4 = _class15 = function () {
   function ViewEngine(loader, container, viewCompiler, moduleAnalyzer, appResources) {
     
@@ -3159,8 +3164,12 @@ var ViewEngine = exports.ViewEngine = (_dec8 = (0, _aureliaDependencyInjection.i
     this.appResources = appResources;
     this._pluginMap = {};
 
-    var auSlotBehavior = new HtmlBehaviorResource();
-    auSlotBehavior.attributeName = 'au-slot';
+    if (auSlotBehavior === null) {
+      auSlotBehavior = new HtmlBehaviorResource();
+      auSlotBehavior.attributeName = 'au-slot';
+      _aureliaMetadata.metadata.define(_aureliaMetadata.metadata.resource, auSlotBehavior, SlotCustomAttribute);
+    }
+
     auSlotBehavior.initialize(container, SlotCustomAttribute);
     auSlotBehavior.register(appResources);
   }
@@ -4027,6 +4036,8 @@ var HtmlBehaviorResource = exports.HtmlBehaviorResource = function () {
       } else {
         instruction.skipContentProcessing = true;
       }
+    } else if (!this.processContent(compiler, resources, node, instruction)) {
+      instruction.skipContentProcessing = true;
     }
 
     return node;
diff --git a/dist/es2015/aurelia-templating.js b/dist/es2015/aurelia-templating.js
index 1ccc71af..9590791b 100644
--- a/dist/es2015/aurelia-templating.js
+++ b/dist/es2015/aurelia-templating.js
@@ -2585,6 +2585,8 @@ export let ViewCompiler = (_dec7 = inject(BindingLanguage, ViewResources), _dec7
       auTargetID = makeIntoInstructionTarget(node);
       instructions[auTargetID] = TargetInstruction.lifting(parentInjectorId, liftingInstruction);
     } else {
+      let skipContentProcessing = false;
+
       if (expressions.length || behaviorInstructions.length) {
         injectorId = behaviorInstructions.length ? getNextInjectorId() : false;
 
@@ -2592,6 +2594,7 @@ export let ViewCompiler = (_dec7 = inject(BindingLanguage, ViewResources), _dec7
           instruction = behaviorInstructions[i];
           instruction.type.compile(this, resources, node, instruction, parentNode);
           providers.push(instruction.type.target);
+          skipContentProcessing = skipContentProcessing || instruction.skipContentProcessing;
         }
 
         for (i = 0, ii = expressions.length; i < ii; ++i) {
@@ -2605,7 +2608,7 @@ export let ViewCompiler = (_dec7 = inject(BindingLanguage, ViewResources), _dec7
         instructions[auTargetID] = TargetInstruction.normal(injectorId, parentInjectorId, providers, behaviorInstructions, expressions, elementInstruction);
       }
 
-      if (elementInstruction && elementInstruction.skipContentProcessing) {
+      if (skipContentProcessing) {
         return node.nextSibling;
       }
 
@@ -2899,6 +2902,9 @@ let ProxyViewFactory = class ProxyViewFactory {
   }
 };
 
+
+let auSlotBehavior = null;
+
 export let ViewEngine = (_dec8 = inject(Loader, Container, ViewCompiler, ModuleAnalyzer, ViewResources), _dec8(_class14 = (_temp4 = _class15 = class ViewEngine {
   constructor(loader, container, viewCompiler, moduleAnalyzer, appResources) {
     this.loader = loader;
@@ -2908,8 +2914,12 @@ export let ViewEngine = (_dec8 = inject(Loader, Container, ViewCompiler, ModuleA
     this.appResources = appResources;
     this._pluginMap = {};
 
-    let auSlotBehavior = new HtmlBehaviorResource();
-    auSlotBehavior.attributeName = 'au-slot';
+    if (auSlotBehavior === null) {
+      auSlotBehavior = new HtmlBehaviorResource();
+      auSlotBehavior.attributeName = 'au-slot';
+      metadata.define(metadata.resource, auSlotBehavior, SlotCustomAttribute);
+    }
+
     auSlotBehavior.initialize(container, SlotCustomAttribute);
     auSlotBehavior.register(appResources);
   }
@@ -3733,6 +3743,8 @@ export let HtmlBehaviorResource = class HtmlBehaviorResource {
       } else {
         instruction.skipContentProcessing = true;
       }
+    } else if (!this.processContent(compiler, resources, node, instruction)) {
+      instruction.skipContentProcessing = true;
     }
 
     return node;
diff --git a/dist/native-modules/aurelia-templating.js b/dist/native-modules/aurelia-templating.js
index 62f454e3..28b25e75 100644
--- a/dist/native-modules/aurelia-templating.js
+++ b/dist/native-modules/aurelia-templating.js
@@ -2772,6 +2772,8 @@ export var ViewCompiler = (_dec7 = inject(BindingLanguage, ViewResources), _dec7
       auTargetID = makeIntoInstructionTarget(node);
       instructions[auTargetID] = TargetInstruction.lifting(parentInjectorId, liftingInstruction);
     } else {
+      var skipContentProcessing = false;
+
       if (expressions.length || behaviorInstructions.length) {
         injectorId = behaviorInstructions.length ? getNextInjectorId() : false;
 
@@ -2779,6 +2781,7 @@ export var ViewCompiler = (_dec7 = inject(BindingLanguage, ViewResources), _dec7
           instruction = behaviorInstructions[i];
           instruction.type.compile(this, resources, node, instruction, parentNode);
           providers.push(instruction.type.target);
+          skipContentProcessing = skipContentProcessing || instruction.skipContentProcessing;
         }
 
         for (i = 0, ii = expressions.length; i < ii; ++i) {
@@ -2792,7 +2795,7 @@ export var ViewCompiler = (_dec7 = inject(BindingLanguage, ViewResources), _dec7
         instructions[auTargetID] = TargetInstruction.normal(injectorId, parentInjectorId, providers, behaviorInstructions, expressions, elementInstruction);
       }
 
-      if (elementInstruction && elementInstruction.skipContentProcessing) {
+      if (skipContentProcessing) {
         return node.nextSibling;
       }
 
@@ -3111,6 +3114,8 @@ var ProxyViewFactory = function () {
   return ProxyViewFactory;
 }();
 
+var auSlotBehavior = null;
+
 export var ViewEngine = (_dec8 = inject(Loader, Container, ViewCompiler, ModuleAnalyzer, ViewResources), _dec8(_class14 = (_temp4 = _class15 = function () {
   function ViewEngine(loader, container, viewCompiler, moduleAnalyzer, appResources) {
     
@@ -3122,8 +3127,12 @@ export var ViewEngine = (_dec8 = inject(Loader, Container, ViewCompiler, ModuleA
     this.appResources = appResources;
     this._pluginMap = {};
 
-    var auSlotBehavior = new HtmlBehaviorResource();
-    auSlotBehavior.attributeName = 'au-slot';
+    if (auSlotBehavior === null) {
+      auSlotBehavior = new HtmlBehaviorResource();
+      auSlotBehavior.attributeName = 'au-slot';
+      metadata.define(metadata.resource, auSlotBehavior, SlotCustomAttribute);
+    }
+
     auSlotBehavior.initialize(container, SlotCustomAttribute);
     auSlotBehavior.register(appResources);
   }
@@ -3989,6 +3998,8 @@ export var HtmlBehaviorResource = function () {
       } else {
         instruction.skipContentProcessing = true;
       }
+    } else if (!this.processContent(compiler, resources, node, instruction)) {
+      instruction.skipContentProcessing = true;
     }
 
     return node;
diff --git a/dist/system/aurelia-templating.js b/dist/system/aurelia-templating.js
index fcd5bfe4..eaeac5c0 100644
--- a/dist/system/aurelia-templating.js
+++ b/dist/system/aurelia-templating.js
@@ -3,7 +3,7 @@
 System.register(['aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aurelia-path', 'aurelia-loader', 'aurelia-dependency-injection', 'aurelia-binding', 'aurelia-task-queue'], function (_export, _context) {
   "use strict";
 
-  var LogManager, metadata, Origin, protocol, DOM, PLATFORM, FEATURE, relativeToFile, TemplateRegistryEntry, Loader, inject, Container, resolver, Binding, createOverrideContext, ValueConverterResource, BindingBehaviorResource, subscriberCollection, bindingMode, ObserverLocator, EventManager, TaskQueue, _createClass, _class, _temp, _dec, _class2, _dec2, _class3, _dec3, _class4, _dec4, _class5, _dec5, _class6, _class7, _temp2, _dec6, _class8, _class9, _temp3, _class11, _dec7, _class13, _dec8, _class14, _class15, _temp4, _dec9, _class16, _dec10, _class17, _dec11, _class18, _typeof, animationEvent, Animator, CompositionTransactionNotifier, CompositionTransactionOwnershipToken, CompositionTransaction, capitalMatcher, ViewEngineHooksResource, ElementEvents, ResourceLoadContext, ViewCompileInstruction, BehaviorInstruction, TargetInstruction, viewStrategy, RelativeViewStrategy, ConventionalViewStrategy, NoViewStrategy, TemplateRegistryViewStrategy, InlineViewStrategy, ViewLocator, BindingLanguage, noNodes, SlotCustomAttribute, PassThroughSlot, ShadowSlot, ShadowDOM, ViewResources, View, ViewSlot, ProviderResolver, providerResolverInstance, BoundViewFactory, ViewFactory, nextInjectorId, lastAUTargetID, ViewCompiler, ResourceModule, ResourceDescription, ModuleAnalyzer, logger, ProxyViewFactory, ViewEngine, Controller, BehaviorPropertyObserver, BindableProperty, lastProviderId, HtmlBehaviorResource, ChildObserver, noMutations, ChildObserverBinder, SwapStrategies, CompositionEngine, ElementConfigResource, defaultShadowDOMOptions, TemplatingEngine;
+  var LogManager, metadata, Origin, protocol, DOM, PLATFORM, FEATURE, relativeToFile, TemplateRegistryEntry, Loader, inject, Container, resolver, Binding, createOverrideContext, ValueConverterResource, BindingBehaviorResource, subscriberCollection, bindingMode, ObserverLocator, EventManager, TaskQueue, _createClass, _class, _temp, _dec, _class2, _dec2, _class3, _dec3, _class4, _dec4, _class5, _dec5, _class6, _class7, _temp2, _dec6, _class8, _class9, _temp3, _class11, _dec7, _class13, _dec8, _class14, _class15, _temp4, _dec9, _class16, _dec10, _class17, _dec11, _class18, _typeof, animationEvent, Animator, CompositionTransactionNotifier, CompositionTransactionOwnershipToken, CompositionTransaction, capitalMatcher, ViewEngineHooksResource, ElementEvents, ResourceLoadContext, ViewCompileInstruction, BehaviorInstruction, TargetInstruction, viewStrategy, RelativeViewStrategy, ConventionalViewStrategy, NoViewStrategy, TemplateRegistryViewStrategy, InlineViewStrategy, ViewLocator, BindingLanguage, noNodes, SlotCustomAttribute, PassThroughSlot, ShadowSlot, ShadowDOM, ViewResources, View, ViewSlot, ProviderResolver, providerResolverInstance, BoundViewFactory, ViewFactory, nextInjectorId, lastAUTargetID, ViewCompiler, ResourceModule, ResourceDescription, ModuleAnalyzer, logger, ProxyViewFactory, auSlotBehavior, ViewEngine, Controller, BehaviorPropertyObserver, BindableProperty, lastProviderId, HtmlBehaviorResource, ChildObserver, noMutations, ChildObserverBinder, SwapStrategies, CompositionEngine, ElementConfigResource, defaultShadowDOMOptions, TemplatingEngine;
 
   
 
@@ -3239,6 +3239,8 @@ System.register(['aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aurelia-
             auTargetID = makeIntoInstructionTarget(node);
             instructions[auTargetID] = TargetInstruction.lifting(parentInjectorId, liftingInstruction);
           } else {
+            var skipContentProcessing = false;
+
             if (expressions.length || behaviorInstructions.length) {
               injectorId = behaviorInstructions.length ? getNextInjectorId() : false;
 
@@ -3246,6 +3248,7 @@ System.register(['aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aurelia-
                 instruction = behaviorInstructions[i];
                 instruction.type.compile(this, resources, node, instruction, parentNode);
                 providers.push(instruction.type.target);
+                skipContentProcessing = skipContentProcessing || instruction.skipContentProcessing;
               }
 
               for (i = 0, ii = expressions.length; i < ii; ++i) {
@@ -3259,7 +3262,7 @@ System.register(['aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aurelia-
               instructions[auTargetID] = TargetInstruction.normal(injectorId, parentInjectorId, providers, behaviorInstructions, expressions, elementInstruction);
             }
 
-            if (elementInstruction && elementInstruction.skipContentProcessing) {
+            if (skipContentProcessing) {
               return node.nextSibling;
             }
 
@@ -3578,6 +3581,8 @@ System.register(['aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aurelia-
         return ProxyViewFactory;
       }();
 
+      auSlotBehavior = null;
+
       _export('ViewEngine', ViewEngine = (_dec8 = inject(Loader, Container, ViewCompiler, ModuleAnalyzer, ViewResources), _dec8(_class14 = (_temp4 = _class15 = function () {
         function ViewEngine(loader, container, viewCompiler, moduleAnalyzer, appResources) {
           
@@ -3589,8 +3594,12 @@ System.register(['aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aurelia-
           this.appResources = appResources;
           this._pluginMap = {};
 
-          var auSlotBehavior = new HtmlBehaviorResource();
-          auSlotBehavior.attributeName = 'au-slot';
+          if (auSlotBehavior === null) {
+            auSlotBehavior = new HtmlBehaviorResource();
+            auSlotBehavior.attributeName = 'au-slot';
+            metadata.define(metadata.resource, auSlotBehavior, SlotCustomAttribute);
+          }
+
           auSlotBehavior.initialize(container, SlotCustomAttribute);
           auSlotBehavior.register(appResources);
         }
@@ -4438,6 +4447,8 @@ System.register(['aurelia-logging', 'aurelia-metadata', 'aurelia-pal', 'aurelia-
             } else {
               instruction.skipContentProcessing = true;
             }
+          } else if (!this.processContent(compiler, resources, node, instruction)) {
+            instruction.skipContentProcessing = true;
           }
 
           return node;
diff --git a/doc/CHANGELOG.md b/doc/CHANGELOG.md
index 80284ee8..438a9fcd 100644
--- a/doc/CHANGELOG.md
+++ b/doc/CHANGELOG.md
@@ -1,3 +1,19 @@
+<a name="1.6.0"></a>
+# [1.6.0](https://github.com/aurelia/templating/compare/1.5.0...v1.6.0) (2017-10-16)
+
+
+### Bug Fixes
+
+* **view-engine:** define metadata for SlotCustomAttribute ([e3474bb](https://github.com/aurelia/templating/commit/e3474bb)), closes [#566](https://github.com/aurelia/templating/issues/566)
+* **view-engine:** singleton instance of auSlotBehavior ([c08db20](https://github.com/aurelia/templating/commit/c08db20))
+
+
+### Features
+
+* **html-behavior:** enable processContent via custom attributes ([7096e66](https://github.com/aurelia/templating/commit/7096e66))
+
+
+
 <a name="1.5.0"></a>
 # [1.5.0](https://github.com/aurelia/templating/compare/1.4.2...v1.5.0) (2017-10-02)
 
diff --git a/package.json b/package.json
index 09e8195c..356913c7 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "aurelia-templating",
-  "version": "1.5.0",
+  "version": "1.6.0",
   "description": "An extensible HTML templating engine supporting databinding, custom elements, attached behaviors and more.",
   "keywords": [
     "aurelia",