App disappears from Win7's ALT-TAB list sometimes

I've been having some trouble with one of my Delphi 2010 projects lately. It seems that sometimes, when I have a form open as a modal dialog, the app stops showing up in the ALT-TAB list until I close the dialog. It's still in the Taskbar, but not in ALT-TAB, whi开发者_如何学编程ch means I can't switch to it without using the mouse.

Running under Windows 7, 64-bit. Has anyone seen this before? Any idea what causes it and how to fix it?

It's a Feature of Windows 7, and not a bug.

The solution is to either remove the 'Tool window' from the Dialog Properties, or to remove 'WS_EX_TOOLWINDOW' from the RC file.

If you want to restore the expected Win XP behavior, just add a DWORD registry key named

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\AltTabSettings

And set the value to 1

You’re welcome :)