VCL-Controls-D2D5-patch.txt

This patch to Delphi 2.01-5.01's Controls.pas fixes an AV issue with
combo boxes and Outlook Express; see:

http://groups.google.com/group/borland.public.delphi.vcl.components.using/browse_thread/thread/e012cea3ea1d258b

Delphi 6 has the same problem, but needs a slightly different patch --
see VCL-Controls-D6-patch.txt.
Delphi 7 and later already incorporate an equivalent fix.

After applying the changes, recompile Controls.pas from the command
line as follows:

> c:\delphi\bin\dcc32 -$D- -$L- Controls.pas
> move Controls.dcu c:\delphi\lib


--- Controls.pas.orig	Sun Jun 09 03:01:00 1996
+++ Controls.pas	Tue Mar 19 20:45:04 2002
@@ -967,11 +967,15 @@
 { Find a TWinControl given a window handle }
 
 function FindControl(Handle: HWnd): TWinControl;
+var
+  PID: DWORD;
 begin
   Result := nil;
   if Handle <> 0 then
   begin
-    Result := Pointer(GetProp(Handle, MakeIntAtom(ControlAtom)));
+    if (GetWindowThreadProcessId(Handle, @PID) <> 0) and
+       (PID = GetCurrentProcessId) then
+      Result := Pointer(GetProp(Handle, MakeIntAtom(ControlAtom)));
   end;
 end;
 
@@ -1271,8 +1275,12 @@
 end;
 
 function IsDelphiHandle(Handle: HWND): Boolean;
+var
+  PID: DWORD;
 begin
   Result := (Handle <> 0) and
+    (GetWindowThreadProcessId(Handle, @PID) <> 0) and
+    (PID = GetCurrentProcessId) and
     (GetProp(Handle, MakeIntAtom(WindowAtom)) <> 0);
 end;