Zen Mode only allowed in one window at a time?

Testing version:
Version 1.0 (566)
What were you doing:
Have multiple Panda windows open (e.g., 2)
What feature did you use:
Zen Mode
What happened:
When I activated Zen Mode in one Panda window it de-activated Zen Mode in the other window.
What did you expect to happen:
I expected Zen Mode to stay activated/enabled in a window, even when I activate/enable it in another Panda window.

After playing around a bit more I see that Show/Hide Toolbar (which is really what I want to do) is a different function from Zen Mode, and one that works as expected (ie I can hide the toolbar on all lists).

What is Zen Mode, then, other than hiding the toolbar?