Opening the source view from the context menu sometimes scrolls to the wrong line number

[mstange]

Steps to reproduce:

1. Load https://share.firefox.dev/4qXrKoY
2. Double-click the second row in the call tree, CCGraphBuilder::NoteJSChild
3. Double-click the third row in the call tree, CCGraphBuilder::NoteChild
4. Note that they scrolled to different parts of the nsCycleCollector.cpp file. This is good.
5. With the third row selected, right-click the second row and click "Show nsCycleCollector.cpp".

Expected results:
Opening the source view from the context menu should scroll to the same place as double-clicking that row would have.

Actual results:
The source view still only shows the "hot spot" for the selected row, not for the right-clicked row.

┆Issue is synchronized with this Jira Task