Example repro :
1. Open 3d Mission Editor
2. Switch to map viewPlace any unit on the map
3. Place anyRMB on unit, Open unit on the map"Attributes"
4. RMB on unit, Open unit "Attributes"Expand "Object: Type" section
5. Expand "Object: Type" sectionLMB click and hold on an unit type, game crashes on release of LMB
6. Scroll Type tree view list box up and down, and LMB on units.