GeezerVison

…window holds the grab

_temp_grab_focus() used grab_current() and focus_get(), which raise
KeyError for windows which were not created by tkinter, such as a native
message box.  Use Tcl window names instead.

The dialog can destroy a temporary default root, and then even "winfo"
fails with "application has been destroyed".

On the Windows CI runners "focus -force" has no effect, because
SetForegroundWindow() is refused for a background process.

The application can lose the focus when the dialog is destroyed, and
"focus" without -force does not take it back.