Don't highlight HTML areas on editing CSS rules in Chrome
You are using bit older version, this has been fixed in newer versions. Chrome Version 74.0.3729.169
and Canary Version 77.0.3812.0
.
after updating chrome, if you still face this issue, here is the work around.
With mouse hover over selected element in DOM Tree.
Without mouse hover over selected element in DOM Tree.
You just need to remove hover from element selection.