Tooltip covered by header

[jribbink]

Describe the bug
Tooltips are covered by the header

To Reproduce
cause an error on one of the first lines in the document and hover over it

Expected behavior
Tooltip should be on top/have highest z index OR be placed below the offending line (instead of above) if it's going to be covrered

Screenshots

as you can see the top of the tooltip is cut off (that's not from the screenshot bounds, but actually how it appears in browser)

Desktop (please complete the following information):

• OS: MacOS
• Browser: Chrome

Additional context
Add any other context about the problem here.