Windows with Qt:Tool flag shown on all desktops on Windows OS

[gvanvoor]

I've noticed that windows which have the Qt::Tool flag set, are shown on all desktops on Windows OS. Does anybody know if there's a way to prevent this from happening? (I don't mind if there's a need to make platform specific calls to do this).

[Chris Kawa]

Tool windows have a WS_EX_TOOLWINDOW style flag set, so the window manager styles them appropriately. This flag is also what causes this behavior and a lot of apps (not just Qt based) experience this. It doesn't seem to be documented anywhere on Microsoft's sites though, so it's hard to say if it's a bug or a feature.

So whether that's intentional or not that's just how tool windows behave on virtual desktops. The only way to prevent this I know is to remove that style flag. You can do that with native SetWindowLong to set GWL_EXSTYLE, but that's basically the same as just not using the Qt::Tool flag and will make your window not look/behave like a tool window.

[gvanvoor]

@Chris-Kawa Thanks for the info. Since the windows that have the flag set in my application need to have it, users will have to learn to live with it.

[Chris Kawa]

@gvanvoor Yeah, unfortunately it's a Windows API behavior, so you'd have to ask someone from Microsoft if that's intended and if there's a workaround.
Maybe you can fiddle with the virtual desktop manager API, but I haven't tried it so can't give you specifics.