Affected versions:
Nightly 68.0a1 68.0a1 (2019-04-11) (64-bit) - TRY BUILD - 20190411095057

Affected platform:
Windows 10 - so far

Steps to reproduce:

• Go to https://developer.mozilla.org/en-US/docs/Tools/Accessibility_inspector
• Open devtools
• Go to the Accessibility tab and enable it
• Dock the devtool panel to the right side
• Click on the "contrast" button for full page audit
• While the filtering is in progress keep resizing the devtool panel

Expected Result:
The filtered tree view, as well as the normal, should be displayed as expected.

Actual Result:
[Filtered] Several elements that are not text leafs and cannot be selected are displayed in the filtered view. There are also no badges displayed
[Expanded tree view] The same elements as above are displayed above the document row that should be the first one. Mentioned elements are unselectable.

Notes:
This can be reliably reproduced for devtool panel dock to the right/left side. I believe this might be due to the page being responsive to the modification of the devtool panel size. Please check attached file.

Overall, the devtool panel is very clunky while resizing if there is a full page audit in progress/loading. Sometimes the whole browser becomes unresponsive and needs to be killed from task manager