Created attachment 102646 [details]
video demonstration of transparent single pixel lines appearing in konsole when moving cursor upwards

Overview:

In Konsole, upon write or scrolling I sometimes get single pixel
horizontal transparent lines.  This appears to happen with any font,
any transparency setting, any Konsole color scheme setting, any screen
DPI (including default).  This can be best seen when running Nethack
or Vi in terminal.  When Konsole is run with --notransparency, I get
similar results.

When "Fusion" application style is enabled, when using drop down
menus (like right click menu or task bar menu) and moving selection
/upwards/, there appear tiny one-pixel horizontal lines that appear to
not be repainted.  This happens on any screen DPI (including default)
and any font setting.

Reproducible: Always

Steps to reproduce:

0. set application style to Fusion
1. open any drop down menu
2. move cursor over each item to lowermost item and then move back

OR

0. open konsole
1. run nethack or vi
2. move cursor to lowest line you can
3. move cursor up

Actual results: Some one-pixel lines appear to be transparent or have
the same color selected item does

Expected results: No one-pixel lines being transparent or having the
same color as selected item

Please see attachment for better understanding