I would try Window>Workspace>Reset Workspace, to see if that brings the Panel back.
Nope, tried that then looked everywhere, undocked windows, everywhere - no colors panel. WOW - CS5 is just a learning workhorse.
With luck, an employee might show up and advise. That would be great customer service!
Just reset the workspace the third time - and now it's there - sigh.
Whew, I was getting worried there for a moment.
Had it not worked, I would have looked into trashing the Prefs file, and letting PrPro generate a new one. Now, with that, one must go in and change anything that had been adjusted, as the values would all have been the default installation.
Glad that this worked for you. Often what will happen is that one will accidentally click a few pixels over, and close a Panel. This can go undetected, until Titler (or whatever) is reopened, or given focus.
I have noticed the precision factor on this new panel is a bit tighter. Lessons learned.