I'm running tc 4.1
I believe that I have found a bug.
The problem is that when an extension contains a .desktop file and the value of the "Name=" field contains multiple words, the script(s) which load(s) the extension strip out the spaces. (e.g. a .desktop file with "Name=My Program" will have the label "MyProgram" in wbar.)
(Note: Of course, if the *.desktop file doesn't have proper "X-FullIconPath=" entry, then there will be no icon.)
This is not a problem with wbar because I can edit /usr/local/tce.icons and reinsert the missing spaces; I can then right-click on wbar to restart it and the labels are then correct. Of course, I'm not going to add /usr/local/tce.icons to my backup because this file is supposed to be generated at system start up.
I'm not very good at reading scripts, but I think that the problem lies somewhere in wbar_setup.sh or wbar_update.sh
You can see this for yourself by installing parole.tcz. It is 14 MB with all the dependencies, but I think that most people already have many of the things that it depends on.