I use MyEclipse on a secondary monitor (the app I spend most of my time on runs full-screen on my primary monitor). Most things work quite well that way, but I have observed the following issues with MyEclipse UML:
1. tooltips occasionally appear on the primary monitor rather than “under the cursor”. Look at the toolbar in the UML editor for examples.
2. At least one button doesn’t work at all on the secondary monitor. To add a stereotype, I have to un-maximize Eclipse, drag the window to my primary monitor, click the little arrow next to the stereotype box on the properties screen, enter my new stereotype, then drag back to my secondary monitor and re-maximize. The button seems to have no effect when maximized on the second monitor.
3. Drag-n-Drop support for sequence diagrams would be really nice
4. I’d love a way to categorize diagrams under a single repository. For now, I make multiple repositories, one for each feature I’m documenting.
I don’t see that multiple monitor support is currently on the ‘feature list’ — so I’m requesting it here rather than listing it as a bug.