Reproduction steps:
1. Open the project
2. Select "GameObject" prefab.
3. Right-click the label (Script) in the Inspector

Actual result: Nothing happens
Expected results: MonoBehaviour context menu appears with default options such as Remove Script

NOTE: Adding another script to the GameObject causes both the warning to go away, and the missing script's title label to respond to right clicks again. Also, note that clicking the gear icon always brings up the context menu.

Reproduced on: 5.5.0a5 5.4.0f3, 5.3.6p2
No reproduction on: 5.3.5f1.