Version:           2.5.3 (using KDE 4.5.2) 
OS:                Linux

The tabs on konsole become sluggish after using konsole for a while.

This problem does not occur immediately, but after using konsole for a while (sometimes after a couple of hours). When choosing another tab using the mouse or keyboard shortcut, it delays for 1 or 2 seconds before showing the selected tab.

This problem is observed on at least 2 different systems. The lastest version of KDE (4.5.3) still has this problem, the other system which shows this behaviour uses kde 4.4.5.

When I lock the screen and unlock it, konsole reacts normally for a while.

This problem has occured with only 2 tabs open.

I am using compositing on nvidia-drivers 195.36.31  and 260.19.12

No high load is occuring when the delay happens.

Reproducible: Sometimes

Steps to Reproduce:
1. have more then one tab open in konsole
2. use it for a while
3. select a different tab


Actual Results:  
The selected tab takes one or two seconds to become active

Expected Results:  
The selected tab is available almost instant.

Locking and unlocking gives a responsive konsole for a while