Display a placeholder item to indicate the destination when the "Add SV/Container" modal is open

[abey79]

As the title says ☝🏻

For now, this should be done only if design and implementation is easy.

[abey79]

@nikolausWest how we feel about something like this?

[nikolausWest]

The indentation in that example seems off by one (would expect it to look like it's a sibling node to "/" here, not a child) but other than that this seems reasonable to me (design is shippable but definitely room for improvement in the future)

[abey79]

Yeah, I agree the box should encompass the collapsing triangle area.