Ok, chill... I got the clock. Deinstalled sailfish theme (DW and a drawing App) and meecast. Then the standbyscreen got crazy. Then I reinstalled sailfish, and afterwards Meecast... and it still didn't go back. Then I installed billboard... and voilà! But I still have a strong hunch that the install of sailfish was behind it.

Also, FYI the (Edit: in the Feed!) icons of the native twitter client and the AP app look weird (round into a square background).