On the menu left hand side CCleaner pro..there is a yellow dot in the 'tools" square...what does that mean
The yellow dot shows that you have a Beta (trial) version of a new feature; in this case it will be the new Software Updater.
I assume that as you are seeing the yellow dot you are running CCleaner version 5.55?
A new version, v5.56, was released yesterday, if you update to that then the yellow dot should go away again because the Software Updater is now (supposedly) fully released.
Nope. I just updated Windows 10 today, which removed CCleaner Pro from my computer as it was 'incompatible', installed and activated my Pro license, and the yellow dot went away. No programs show in either window: neither 'programs to update' nor 'up-to-date programs'. This happened before, and they had me go back to an earlier version because they said it was still in Beta.
It is now supposedly out of Beta which is why there's no yellow dot, but you are not the only one to report that it still isn't working properly (yet?).
Empty windows like you report are just one of the reported problems. (Along with wrong version numbers being found and 'Unknown' programmes being found to update).
I'd just ignore it, even if working it only finds/updates certain 'selected' apps anyway. (The ones hosted on Filehippo).