Fixes the sidebar taking keyboard focus away from the pane you just clicked into.
The panel highlights the row for whichever tab becomes active, but doing so also moved DOM focus into its tree — so reacting to you focusing something else took the keyboard off it. This was most visible with a terminal pane, where a pane that has lost focus looks identical to one refusing to accept typing: it appeared to freeze a few seconds after launch, and recovered as soon as this sidebar was closed.
Clicking a row and arrow-key navigation are real interactions with the panel and still take focus as before.