Steps to repro:

1. Open attached project and 'test' scene;
2. Click on Scene view tab in Editor;
3. Launch Play mode;
4. Open Frame Debugger (Window -> Frame Debugger);
5. Click "Enable" button to enable Frame Debugger;
6. Click on any event inside FD window and observe the event details panel on the right.

Expected result:
Frame Debugger shows event details.

Actual result:
Frame debugger doesn't show render event details after launching Play mode from active Scene view tab. See attached video.

Workaround:
Re-enable Frame Debugger by clicking Enable button again or by launching Game view tab and re-enabling Frame Debugger.

Notes:
- Reproducible in 5.6.0b5, 5.6.0b4, 5.5.0p4, 5.4.4p1;
- Reproducible on both OSX 10.12.2 and Windows 10;
- Possible symptom of the bug is that Scene view tab is set active after enabling Frame Debugger in launched Play mode (usually when entering Play mode Game view tab becomes active by default). That might confuse Frame debugger and be the reason of the bug.