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

Reply to Windows with Qt:Tool flag shown on all desktops on Windows OS on Wed, 04 Jan 2023 13:26:02 GMT

Chris Kawa — Wed, 04 Jan 2023 13:26:02 GMT

@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.

Reply to Windows with Qt:Tool flag shown on all desktops on Windows OS on Wed, 04 Jan 2023 13:14:21 GMT

gvanvoor — Wed, 04 Jan 2023 13:14:21 GMT

@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.

Reply to Windows with Qt:Tool flag shown on all desktops on Windows OS on Tue, 03 Jan 2023 14:38:38 GMT

Chris Kawa — Tue, 03 Jan 2023 14:38:38 GMT

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.