Steps to reproduce:
1. Download project from provided link and open it
2. Open "ChrisTest" scene
3. Open profiler
4. Start play mode
5. Move your mouse(everything moves smoothly ~60fps)
6. Select "Main Camera" gameObject in hierarchy window without exiting play mode
7. Move mouse again
-Observe performance spikes in the (CPU usage) profiler (<30fps)

Actual result: Huge performance spikes when the main camera is selected.
Expected result : selecting gameObjects in the hierarchy should not result in the bad performance.

Reproduced on: 5.5.0b4, 5.4.1f1, 5.3.6p5