Exact version: 7.00 (2012-09-23) Multilanguage x86, Currently available to download.
Host: Windows 7 x64 Enterprise.
When I open a project in the IDE and try to view second source file, the IDE fails to display that second file. However I am able to display one .c file and .rc script.
Some hints discovered:
Microsoft Spy++ attached to Pelles' MDI client shows that WM_MDICREATE returns NULL handle:
<00009> 03CA06C8 S WM_MDICREATE lpmdic:0028F138
<00010> 03CA06C8 R WM_MDICREATE hwndChild:(null)
<00011> 03CA06C8 S WM_MDICREATE lpmdic:0028F138
<00012> 03CA06C8 R WM_MDICREATE hwndChild:(null)
OllyDbg hooked into SendMessageW shows that MDICREATESTRUCT->szTitle is NULL.
In my opinion a NULL caption causes the failure. Very often passing title=NULL to CreateWindowEx forces a failure.
The x64 release of the IDE does not fail like x86. Leaving 2 project source files open while closing the IDE, and then restarting it will re-open both, but the 32-bit version of Pelles' IDE just opens only the first stored source file.