I create a new message. When I want to adjunct a file, I select de Adjunct... menu. Appear a dialog window to select the file, but when I want to scroll it, is very slow and when finally it scroll (lasts several seconds) I select the file and lasts several seconds again to choose.

Reproducible: Always

Steps to Reproduce:
1. Create a new email
2. Adjunct a file
3. 
Actual Results:  
I select the file to attach, but it lasts a long time. 
Kmail doesn't crashes.

Expected Results:  
Do not get stuck while moving the scrollbar or select a file. 

Moving the scrollbar or selecting a file consumes a lot of processor.