* STEPS TO REPRODUCE: 1. Inspect any page 2. Go to Timelines 3. Take a recording 4. Click "JavaScript & Events" 5. Switch from "Events" to "Call Trees" 6. Go to a different tab 7. Go back to Timelines => "Events" is selected
This is also true for switching from "Call Trees" to "Events". It seems like whatever was selected when it was shown for the first time is the setting that is used.
*** This bug has been marked as a duplicate of bug 192451 ***