Windows created with yad lack the _NET_WM_WINDOW_TYPE_DIALOG attribute by default.

[loathingKernel]

The windows created by yad don't have the required information to be treated as dialogs under X11. For example xprop _NET_WM_WINDOW_TYPE on any yad window results in the following output

_NET_WM_WINDOW_TYPE(ATOM) = _NET_WM_WINDOW_TYPE_NORMAL

In comparison windows created by qarma or zenity return the following

_NET_WM_WINDOW_TYPE(ATOM) = _NET_WM_WINDOW_TYPE_DIALOG, _NET_WM_WINDOW_TYPE_NORMAL

This results in window manager rules that refer to the window type to apply properties (such as centering them etc) on all dialogs not working for yad and having to rely on WM_CLASS, which is a problem since it's configurable.

I believe that because of the intended use of the program, the windows should be dialogs by default. Using --splash doesn't help much either as splash dialogs usually don't appear in the taskbar or the pager, meaning they are less useful in most cases than dialogs.

[v1cont]

you can use --window-type argument which was added in v14.0