Alt-space does not open the system menu on Windows

[sshock]

On Windows I am unable to open the system menu with the keyboard shortcut alt+space.

Steps to reproduce:

• cargo run --example window
• Hold down Alt and hit Spacebar.

Expected results:

• It should show the system menu.

Actual results:

• It does not show the system menu.

You can open the system menu by clicking on the window's icon in the top-left corner, but not by pressing alt+space. Being able to trigger it with alt+space is expected behavior for all well-behaved apps on Windows.

[ajtribick]

Looks like this is related to handling of the WM_SYSKEYDOWN and WM_SYSCHAR messages. According to Microsoft's documentation, these should be passed to DefWindowProc, as far as I can see this never happens for WM_SYSCHAR and only happens for WM_SYSKEYDOWN in the case of ALT+F4.

If I remove the handling of WM_SYSKEYDOWN and WM_SYSCHAR entirely by removing these cases from the match in public_window_callback_inner, the ALT+Space combination works again, but I believe this would also prevent the application from receiving ALT+{any key}.

[sshock]

Interesting. If it's helpful and you want to send me a patch I could maybe help test whether or not it prevents the app from receiving any other alt combinations (I could test with alacritty).

[sshock]

Thanks! Looking forward to seeing this in downstream project alacritty.