Tab-Stack (thick colored line) blocks half of all the titles on every tab

ColorTabs 31.2.0

The Tab-Stack below the tabs (the thick colored line) is blocking the tabs web site titles exactly at the half way point all across the Firefox window, left edge to right edge.

I would like it to go back to old way where I could read all the web site page titles but can not find any controls other than turning the Tab-Stack on/off selector. Interestingly, after turning this feature off, the part of open window below where the Tab-Stack was just moves up and still blocks the lower half of all tab web site titles.