Since you are using gtk widgets and the thunar layout is quite close to the gtk+ filechoosers, can I suggest you read the following critique of the initial concepts of the filechooser design. http://bugzilla.gnome.org/show_bug.cgi?id=331404 There are a number of usability issues that apply equally well to thunar. Hope that's useful.
Probably the only real "short-coming" that applies to Thunar is that the path bar "runs out of width". *** This bug has been marked as a duplicate of bug 2060 ***
Yes , essencially the pathbar width (that is now fixed in filechoose btw) One other point applies I think and that is getting some users unfamiliar with thunar and seeing how and where they get stuck. It is near impossible to spot some of the failing in our own designs because we are use to it and see no problem. We are trapped by the same preconceptions that cause the shortcomings. I regard it as a fundemental test when I produce an interface to sit a user down and just watch. If he asks for help I polity refuse and ask him to try to find his way or to explain why he is stuck or confused. Hopefully some of my enhancement posts with highlight a few points while I am still at the new user stage with Thunar. Plus hopefully some useful solutions/suggestions. Thanks again for Thunar . I've never really found an FM on Linux that does what I want. I think Thunar is coming close.
Well that's actually what we did for Thunar in various places.