Created attachment 269990 [details]
gdk_window_get_state() test app

It looks like the first call to gdk_window_get_state() returns the old value after an unmaximize.

The simple testcase (attached) registers a callback and prints out window state and size. We geht:

# Normal window
state = 0x80, width = 200, height = 200
# Maximize
state = 0x184, width = 1920, height = 1014
# Unmaximize
state = 0x184, width = 200, height = 200
# Move window
state = 0x80, width = 200, height = 200

Decode:
    0x80 == GDK_WINDOW_STATE_FOCUSED
   0x184 == GDK_WINDOW_STATE_FOCUSED | GDK_WINDOW_STATE_MAXIMIZED |
            GDK_WINDOW_STATE_TILED

Downstream user is Geary, where this behavoir makes Geary fail to restore the correct window state when the user unmaximizes, then closes the window.