Selected Tab can not be set before the pane has been added to a panes collection

Question

Greetings. 
 
 My name is Seong ha, Choi. I have a problem such as above title in my trados studio 21 sr1. 
 
 How can I fix the problem? 
 
 Please, give me a help. Thanks a lot. 
 
 Best Regards, 
 Seong ha, Choi

Oana Nagy · Answer

Hello Seong Ha Choi , 
 Please try repairing/resetting Studio which will normally fix this- 
 gateway.sdl.com/.../communityknowledge

Trados Studio > 1. Trados Studio

Selected Tab can not be set before the pane has been added to a panes collection