Something I noticed lately: You've got these four icons in the toolbar, two for rotation (CW and CCW), and two for flipping (vertical and horizontal). The way they work is inconsistent if you select several objects: The rotation icons rotate each object separately on its own center. The flip icons flip all objects together along a shared center.

I'm not sure if this is intentional or not, but I thought I should at least bring it to your attention. As a user I'd prefer all four icons to work on all objects together, not individually.

Cheers, Michael