Handle input extension events when making a window native

Handle input extension events when making a window native

It may happen when turning a client side window into a native window
that the window, or some of its children with the same native parent
have extension events enabled, and thus have an input window enabled
for the native parent which needs to change as the window is made
native.

We fix this by temporarily disabling extension events on all the affected
windows while we create the native window, and then reenable them afterwards.

This fixes: https://bugzilla.redhat.com/show_bug.cgi?id=544624