Repro steps:
1. Open attached project "FrameDebuggerTest"
2. Open scene "Sample Scene"
3. Enter Play Mode
4. Main Menu -> Window -> Analysis -> Frame Debugger
5. Click "Enable" in the Frame Debugger's window
6. Move the mouse to the Game View
7. Observe the Frame Debugger Window

Actual: The draw call count changes until you press something in the Frame Debugger Window

Reproducible with: 2017.2.5f1, 2017.3.0a6, 2017.4.17f1, 2018.2.19f1, 2018.3.0f2, 2019.1.0a12

Notes:
- This kind of behavior can also be observed when moving the slider which is at the top of Frame Debugger Window to the far left

Fixed in: 2019.2.0a1
Backported to: 2018.3.3f1, 2019.1.0a14