About tab malfunction

[ O S ] Windows 10
[Server] XAMPP 7.3.22
[ PHP ] 7.4.10
[ D B ] MariaDB 10.3.15
[ W P ] 5.5.1-ja

It may be only my environment, but I have a problem because it is occurring.

“Tabify Edit Screen” can be used to display three display items on a fixed page.

I am setting custom fields using “Advanced Custom Fields”, but there is a place to set “Hidden items” in the setting items, and check “Content editor” in the setting items in it If you select a tab other than the first tab set in the “Tabify Edit Screen” and immediately return to the first tab, the hidden “Content Editor” will be displayed. It has become like.

Furthermore, I am using the “classic editor”, and even though the menu icons should be side by side, they are eroding the input part of the editor.

This phenomenon also occurs in an environment where “Advanced Custom Fields” is not used.
In addition, considering browser dependence, we have confirmed reproducibility on Google Chrome and Windows Edge.

Maybe it’s not working well because of the “classic editor” environment.

If you are suffering from the same symptom and have now resolved it, could you please teach me how to deal with it?

I look forward to working with you.