Steps to reproduce:

1. Open MonoDevelop
2. Maximize any window
3. Move the MD window to the top of the screen so that Mission Control shows up
4. Try docking the MD window to that Maximized window so that it's split screened
- Note that MD crashes upon docking
- This does not happen if the MD window is first docked to a new desktop and then docked to another one in split-screen

Expected outcome: MD docks to the side of the window
Actual outcome: MD crashes upon docking

Reproduced on 2017.1.0b6, 5.6.1p1, 5.5.3p1

Reproduced on MonoDevelop 5.9.6
Doesn't reproduce on MonoDevelop 4.0.1

Same behaviour on OSX 10.11.6 and 10.12.4