Hello!
DO 8.2.2.0U.
If I select Tools->Search, I get proper panel.
However if I choose Synchronize or Search for duplicates, a new lister opens with selected panel.
I believe it is wrong.
X.
If you edit the buttons you'll see they run different commands. One will just toggle the panel while the other will have an argument which causes a layout (new lister) to open.
You can edit them so they all open panels if you like. (That's what I've done.)