Rated 5 out of 5 stars
The problem under FF 19 is that TGM and Tab Mix Plus conflict. I got back to almost exactly my preferred layout by disabling Tab Mix Plus and enabling Tab Utilities in order to get multi-row tabs. Only problem is that Tab Utilities cannot precisely control variable width of tabs, so all my tabs must now have the same width. That is a small price to pay to get back TGM and multi-row tabs.This user has other reviews of this add-on.