Conflicts with Tab Mix Plus/open tab next to current.
i have my new tabs set to open after the current tab (so multiple links opened in new tabs would open one after the next)
Anyhow, at times, instead of opening the new link in a tab next to the current tab, it opens it next to the tab, next to the current tab.
So for instance
Facebook | Mozillazine | Google
I open an app like farmville with middle click
Facebook | Farmville | mozillazine | etc
There is a random chance it will open normally, however if you have recently closed a tab next to the current tab, with the HiQ extensin enabled it might become
Facebook | Mozillazine | Farmville | etc
and Mozillazine suddenly becomes the active tab when this occurs.
I have verified the behavior stops with the divx tab disabled, and its not exactly easy to test with tabmix plus disabled (since firefox doesn't open new tabs next to each other by default)
edit - added video to top