Blockbase: Jumping Close Navigation Button

[iamtakashi]

In Blockbase, a part of the ponyfill CSS changes the position of the close navigation button. That seems to be making the button jump.

If I disable the part of CSS, it seems to resolve the issue.

Why do we need this? Is it a leftover fix that we needed before? Can we now get rid of it?

[mikachan]

I'm not sure why we added this originally, my guess is that it could've been to fix the position of the close button when the admin-bar is visible. I've opened up a Gutenberg PR to fix this: WordPress/gutenberg#41664

Removing these styles in Blockbase seems to work fine. Opened up a PR for this too: #6082