Oliver Schneider wrote:
VIDE/LCC once had such an editor. It was not as elaborate as is Visual Studio's dialog construction tool, but it worked.
If I remember correctly, it was partially OpenSource.
Screenshot: http://assarbad.info/stuff/tutorials/nonvcl/reseditor.png
Related links: http://www.cs.virginia.edu/~lcc-win32/ (LCC) http://www.objectcentral.com/downloads.htm (source code of VIDE!!!)
I use VIDE as a test tool. It helped in identifying a bug in CreateWindowsEx. Thanks, James