I think I've found a bug in window re-sizability.
When I open Highlighting, it adds to the left of my active window....but I cannot resize it (smaller):

If I move it to the Right, I can resize it the way I want:

If I then move it back to the Left, I can now resize it:

It appears this has been around a while:
http://community.logos.com/forums/p/4046/31170.aspx#31170