Alt-4 seems not to work. Alt-[1-3,5-0] works perfectly. I have no problems to use alt-4 on a wheezy x86-64 vm. Also tried on a vm machine with fresh installed Debian Jessie x86-64 with the same result: not working alt-4.
Hi, this KDE bug may be relevant: https://bugs.kde.org/show_bug.cgi?id=310881 Andras