#2134 Scrolling doesn't repaint properly in GUI mingw-get

[Kevin Scott]

A minor issue, which may depend on font size or window dimensions. When the list of packages is scrolled, the repaint may leave extra lines on the text.

Inside the attached .tar.gz are 3 images to show the issue:
instMgr-started.tif: what it looks like when started up, i.e. normal appearance
instMgr-scroll1.tif: what it looks like after scrolling, i.e. slightly messed up
instMgr-scroll2.tif: after flyover with the mouse cursor, appearance becomes good again

Conditions:
Running mingw-get version 0.6.2-beta-20131004-1

The OS is XP, and the "display" control-panel settings are:
Theme: Windows Classic (Modified)
Appearance: Windows and buttons: Windows Classic style
Appearance: Color scheme: Windows Standard
Appearance: Font size: Large
Screen resolution is 1024 x 768 pixels.