Expand frame working only for first 10 frames

[mireq]

Click handler finds n-th (n is frame depth) line of frame and expands parent. Default are 10 lines visible. If depth is higher browser raises:

Uncaught TypeError: frame.getElementsByTagName(...)[i] is undefined
    addToggleFrameTraceback http://localhost:8000/?__debugger__=yes&cmd=resource&f=debugger.js:26

[davidism]

Please rebase this to 2.0.x:

git rebase --onto origin/2.0.x origin/main
git push -f

Then change the target of this PR using the edit button to the right of the title.