When systemsettings is opened, the initial selection mark is on the very first item, Account Details.
Using the cursor keys, I can select any other item in that group, but not the group below.
Similarly, after I select an item in any group below with the mouse, I can freely navigate through all items and groups using cursor keys, but I cannot reach the Workspace group from there, either.

Also, if the selection is in the Workspace group (either from clicking or by pressing the first letter of one of the items), then I can move in that group, but not leave it.

Interestingly, when I started systemsettings with English locale (to find out the English names of the groups and items), that bug does not occur. So it may be localisation related.
I'm running a German KDE 4.11.2. I didn't test any other translations.

Reproducible: Always

Steps to Reproduce:
Open System settings in German, move selection mark around with the cursor keys.
Actual Results:  
The selection mark cannot cross the border from/to the "Workspace Appearance and Behavior" group.