I start messenger. Using Open Live.
The first time it loads, it shows my custom contact list window.
Then, I press the Close button, LM stays active in the system tray.
Then, I double click the system tray icon, and then in the dashboard,

-the DP isnt visible anymore, instead I see small parts of the DP border
-the name isnt visible anymore, instead I just see the drop down menu caret
-the personal message isnt visible anymore, instead I just see the caret. However, the part where you enter the text is small but visible. When I click it, and then click somewhere else, the personal message gets reset to <enter text> or however it is in english.

What could possibly cause this?

Try reading here:

Willz's reply to [Update] SexySkin 1.1.500

The problem occurs when you have removed toolbar buttons by just changing them to "layoutpos=none".....the way around it is described above, you have to wrap a conditional element around the buttons and set that to layoutpos=none

Thats not the case here, I was using open live, but removed the window border alltogether in all the ui files. The other small edits were saved and readded in a new, clean open live, which fixed the problem.