Code review comment for lp:~mzanetti/unity8/buttons-in-panel

Encapsulating panel state in a singleton is a good idea. Multi-monitor will complicate things, but one thing at a time.

Works well here. Approved

 * Did you perform an exploratory manual test run of the code change and any related functionality?
Y
 * Did CI run pass? If not, please explain why.
Y
 * Did you make sure that the branch does not contain spurious tags?
Y