This is mostly a bug fix release. For a more complete list and detailed
description of them see the documention and ChangeLog.

Critical Bugfixes in 1.3.1:
    * Fix for not hiding submenus if menuDelay is set.
    * Fix crash when moving transient windows (Dialogs) between Workspaces,
      #3088856.
    * Fix crash when SystemTray was rotated 90/270°, #3188223.
    * Fix potential crash when gettting an UnmapEvent before a FocusEvent.
    * Fix potential crash on accessing NULL-pointer.

Other Bugfixes:
    * Fix wrong width calculation of Systemtray, #3150939.
    * Fix initial placement of WindowMenu, #2731524.
    * Fix incorrectly shown alpha values in Menus, #3187373.
    * Fix render 'sunken' Textures correctly.