Description of problem:

There are some visual artifacts on horizontal scrollbars in the clearlooks
theme, as illustrated in the attached screendump.

Version-Release number of selected component (if applicable):
gtk2-engines-2.7.4-3

How reproducible:
easily in many different gtk2 programs

Steps to Reproduce:
1. open up for example evolution
2. resize the message view to provoke a horisontal scrollbar. 
3. Sometimes when you stop artifacts like the one in the attached screenshot
will appear. 

  
Actual results:
a solid or dotted line often appear in the non-blue part of the horizontal scrollbar

Expected results:
as vertical scrollbars

Additional info:
the artifacts can be removed by forcing a rewrite by placng another window over
the scrollbar and then removing it again.