The free version is limited to three tabs per window max and several other restrictions.It does not allow you to reorder or rename tabs, use middle-clicks to close tabs, and does not support multi-monitor setups.
Some Context Menu Items are Missing, Last commit 2013, website no longer up. See https://code.google.com/archive/p/cubicexplorer/source/default/commits
I suggest (my personal favorite app) Directory Opus be added in this list.