Column block: Add block icon (+) is hidden under column toolbar

[mapk]

Describe the bug
There's a situation that when the column in a Column block is selected, a user can hover just in the right spot to reveal a hidden "Add block" inserter icon.

To reproduce
Steps to reproduce the behavior:

1. Add a Column block.
2. Add some content to a column.
3. Click up to the Column level and hover right above the content block within the column.
4. Observe the Inserter + icon appear but hidden under a toolbar.

Expected behavior
I expect the icon to be completely visible or not show at all. It's a weird situation.

Screenshots

Desktop (please complete the following information):

• OSX
• Firefox 68.0
• Gutenberg 6.1.1

[karmatosed]

I 'think' this should just be a case of a z-index bug and maybe doesn't need design? For me, it should be visible no matter what. I'll swap out labels but happy to change that.

[ZebulanStanphill]

Related: #13571

[enriquesanchez]

Discussed during today's design triage meeting in Slack (login required).

The team agreed that applying z-index would not take care of the underlying issue. It was suggested to explore only showing block mover icons when the block is selected and to perhaps rethink sibling inserters to find different ways they can exist.

[mapk]

Only showing block movers when the block is selected is being worked on here: #16745

[mapk]

Actually, nevermind... that other one is a duplicate of this one which has already been merged. #17315

[mapk]

Just tested and this isn't resolved because the mover icons aren't the issue. Darnit! So still need to rethink the Sibling Inserter here and the interaction.

[karmatosed]

@mapk would you mind testing this on master please? I am not getting it right now but this could be me missing a recreation step.

[karmatosed]

It would be great to have this worked on as part of #18667

[mapk]

Just tested again today in master. I still see the issue. Albeit it was a bit more difficult to get to this problem though due to traversing up from nested columns seems harder nowadays without the additional parent block borders.

Single Column selected:

and Columns block selected:

[youknowriad]

This seems fixed in my testing. We still have the issue that it's impossible to insert a block at the beginning of the column but this is tracked separately #16094