* Fixed potential access violation, use runtime user dir instead of tmp dir
    for single instance socket.

* Fixed an issue with losing icons on desktop, when file name has a '[' char.

* Added a missing tooltip for 'New Window' toolbar button.

* Fixed an issue when single instance socket' directory did not exist (see
    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874753).