Version:           svn trunk (using KDE 4.4.5) 
OS:                Linux

After a long time painting (hours when I discovered the bug, and then >10 minutes in the retest), the color selector that popups with a right-click becomes really slow. This becomes EXCRUCIATINGLY slow when using a tablet (probably because it generates much more events), to the point of having to wait 2~3 minutes for the color picker to finish processing after I try to pick a color if I commit the deadly sin of sliding the tablet even slightly over it, even by accident.

Reproducible: Sometimes

Steps to Reproduce:
I only tested once, and this is a 2-weeks old Krita build, but I haven't seen any fix in this area in the commits so I'm sure it can be reproduced in current trunk.
1.- Create a new image.
2.- Make many layers of a decent size (800x600 or more).
3.- Paint to your leisure or fill with the layers with garbage. Try to do this for at least 5 minutes.
4.- If you have a tablet, use the stylus button to spawn the color selector and try to select a color.
4b.- Or if you have a mouse, do it with the right click button and click and slide the pointer over the color selection area for a good while.

Actual Results:  
If done with a tablet:
4.- Enjoy a 2~3 minute Krita hangup.
If done with a mouse:
4b.- Krita will only hang up for a few seconds, which is still a noticeable slowdown compared to an instant color selection when one starts painting with a freshly opened Krita.

Expected Results:  
The color selector behaves smoothly just like with a freshly opened Krita.

System specs: DELL Inspiron with a Pentium Core Duo 1.66 Ghz, with 2 GB ram, and Nvidia GeForce 8600M GT.
2 weeks old Krita build.