I think it rather indicates that the object is being monitored for changes.
You can also invoke that via a like-sounding command in the context menu.

Stéphane Rollandin <lecteur at zogotounga.net> schrieb am Mi., 17. Okt. 2018,
21:31:

> Hello all,
>
> In an object explorer, when one clicks twice on a list item it gets
> displayed in red. This is supposed to indicate that the item is
> selected, but actually selecting another item does not update the
> previous one, which stays highlighted. This seems like a bug.
>
> Also, is that notion of selected item used by the object explorer at
> all? If not, we may get rid of the color cue altogether.
>
> Stef
>
>
>
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