Visual flaws with pinned tabs

[shield72]

Hello,

when multiple rows of tabs are present, the borders of pinned tabs become drawed through them.

This happens also when Classic Theme Restorer has been disabled. In case the mouse hovers over a pinned tab, the corresponding lines disappear temporarily (as seen in the screenshot below).

Firefox v44.0.2, Tab Utilities fixed 1.5.2015.09.12.1-let-fixed, Windows 7. With Tab Mix Plus it looks fine (but no tab stacking, of course :-/).

This is really unaesthetic and annoying.... a fix would be welcome!

Thank you for keeping Tab Utilities alive! -)