Steps to reproduce:
1. Open the attached project in "bug.zip"
2. Select "Two Column Layout" in the Project window if not already checked
3. Select the "SampleScene" file from "Scenes" folder, right-click it and select "Copy Path"
4. Check your clipboard, it should be "Assets/Scenes/SampleScene"
5. Select and right click on packages, then select "Copy Path"

Expected result: You can't press "Copy Path" when selecting the "Packages" folder.
Actual result: You can press "Copy Path" when selecting the "Packages" folder, and when you press "Copy Patch", it copies last selected folder/file in the right column.

Reproduced in 2018.2.11f1, 2018.3.0b5, 2019.1.0a4