Multiple block can be in a "isHovered" state

[afercia]

Noticed while investigating on improvements for #8033.

There should be just one block in a "isHovered" state at a time. However, the implementation fails and multiple blocks can be in a "isHovered" state, with the related UI and styles displayed:

To reproduce:

• hover a block
• hover the "More Options" ellipsis button on the right
• wait for the tooltip to appear
• at this point, move the mouse up vertically, to hover the right area of the previous block
• both blocks are now in a "isHovered" state

Same happens with the "block mover" buttons on the left.

Repeating the same steps for all the blocks above, all the blocks become "isHovered".

[designsimply]

Tested and confirmed and found that this only happens when moving the mouse very quickly from one control element after the tooltip is triggered to another control element such as the more options, mover, or the block label that appears on hover. (1m20s)

^{Tested using WordPress 4.9.7 and Gutenberg 3.3.0 both in Safari 11.1.2 and Firefox 61.0.1 on macOS 10.13.6.}

Related: #2122

[afercia]

In my testing it happens also without being very fast when moving the mouse. It seems to always happen when moving the pointer vertically in the area highlighted in the screenshot below:

[designsimply]

For completeness, may I ask what OS and browser versions you are using for testing?

[afercia]

I've tested it on mac, latest Chrome and Firefox.

[jorgefilipecosta]

Hi @afercia thank you for reporting this issue. I tried to replicate this issue after all the design changes that happened and I was not able to do it, it was probably solved as a side effect of the design changes. If I missed something feel free to reopen the issue.

[afercia]

Hi @jorgefilipecosta yep, can't reproduce any onger. Thanks.