How to play on Test with customUI (Solution)
 

since LU38 did change quite some things, i figured you get rid of all the crashes and issues on test with renaming/copying_away the following files:

eq2ui_inventory_inventory.xml
eq2ui_newcharscene.xml
eq2ui_newcharscene2.xml

In the EQ2 Interface Changes forum you will find a listing of all changes that effect the Test Server. It's usually a good idea to check there once a test patch is applied so that you know what windows to look out.

FYI: There are more windows than those you listed that others should be aware of: Link

oups, wasnt aware of that section, thanks :)