Fix: Add Block Icon Not Visible

[Luciaisacomputer]

Description

In #11345 it is noted that the add block button does not appear visually to users when tabbing through blocks. The fix for me seemed to be adding a :focus state for the toggle button itself which sets the opacity of the bottom to 1, making it appear.

It's possible that some class names changed which cause this as I did see a .is-visible class reference. There is a parent Div node that does receive the class on focus. Hopefully someone knows the original implementation details and can speak to that.

How has this been tested?

I opened edit post screen in Chrome, Safari, Firefox, IE11, and Edge. Then I tabbed backwards through several paragraph blocks. Each time the button appeared for me.

Screenshots

Types of changes

Bug fix

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.

[mtias]

Thanks for the contribution. This already seems addressed by #11685