How to reproduce:
1. Download attached project file
2. Right click on "a" folder in Project Window (Notice that "Test" method is not selected)
3. Right click anywhere on Project folder (Notice that "Test" method is shown as selected)
4. Right click mouse button again ("Test" method shown as deselected)

Expected result: Menu.SetChecked method shouldn't show selected if folder is not selected
Actual result: If you select the folder and then right click it, the "Test" command will not be checked. If you right click it again, then it will be checked. Likewise, if you deselect it and open the menu, the check mark will still be there the first time

Reproduced with: 5.5.4f1, 5.6.3p2, 2017.1.1f1, 2017.2.0b10, 2017.3.0a7