OK, this is weird. I downloaded and extracted Firefox 3.5 from Mozilla and put it into:

~/apps/firefox/firefox3.5

When I go into that folder in Dolphin and click on the shell script file "firefox", it starts up firefox and has the blue scrollbar and is version 3.5.3. This is correct.

I added (via Menu Editor) an App Launcher Icon that points to:

~/apps/firefox/firefox3.5/firefox

THAT is the SAME shell script file.

When I start Firefox 3.5.3 from that Application Launcher icon, it runs a Firefox with a GREEN scrollbar! And even though the "help->About" says it's 3.5.3, I can tell it's not because certain javascripts run slower like they do in 3.0.12! I can see this difference when I start from the file in Dolphin!

What could possibly be causing this?!