Dragging a reusable multi column block into itself, the block is messed up or removed.

[Fujix1]

When I drag a reusable block with a multi column block into itself, the block is messes up or removed.
This issue is similar to #9303
but it's not for a reusable block.

To Reproduce
Steps to reproduce the behavior:

1. Insert a multi column block.
2. Put any blocks in each column.
3. Register the multi column block to a reusable block.
4. Drag the block into itself.

Expected behavior
When a multi column block is in a reusable block, it should be locked and not accept dragging.

Screenshots

Desktop:

• OS: Windows 10
• Browser: Chrome 70.0.3538.102, Firefox 63.0.3

Gutenberg version 4.5.1 and the Test Gutenberg web site.

[talldan]

I gave this a test as there were some recent fixes to drag & drop in relation to columns.

Unfortunately it still seems like an issue.

What's unusual is that the user can't edit a reusable block normally without clicking the 'Edit' button, but can still modify it by dragging a block into the reusable block. That seems inconsistent.

[talldan]

Looks like I forgot to remove the Needs Testing label last time. I've just retested this and it still seems to be an issue:

On some of the dropzones there didn't seem to be any effect though.

I think ideally the dropzones would be disabled unless the reusable block is being edited.

The second thing is that a user shouldn't be able to drop a block on itself, and I think in that case those dropzones within the block being dragged would ideally be disabled as targets.

[noisysocks]

I think ideally the dropzones would be disabled unless the reusable block is being edited.

The second thing is that a user shouldn't be able to drop a block on itself, and I think in that case those dropzones within the block being dragged would ideally be disabled as targets.

Agreed.