Some possible improvements:

• Small border-radius for focused rows
• Shift arrow a bit to the right? Currently it's overflowing a bit from focused rows, but the current alignment might be necessary in Debugger's SecondaryPanes?
• Arrow vertical alignment: hard to get right, it's shifted with a margin-top: -1px which is ignored on 1x displays.
• The indent guide could use the same colors as the indent guide in Inspector's Markup view:

.theme-light {
  --markup-outline: var(--theme-splitter-color); /* light gray */
}
.theme-dark {
  --markup-outline: var(--theme-selection-background); /* dark blue */
}

Hi! I would like to contribute to this project, can I work on this?

Yes, please!

Assigned to you.

Honza

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Hi @Honza Can I get this please

Solved this bug
Can I submit the patch?

Sure assigned to you.

Depends on D128878

Hello bomsy

Here is a first try at fixing this, Please let me know if there is anything to add or modify

This good-first-bug hasn't had any activity for 2 months, it is automatically unassigned.
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Hi there,

I see there is some work on this bug. Can i take it over and use the existing code to get this wrapped up?

Thanks,
Samuel