I am also having the same problems. I reverted to version 2.5.1 that i found in an old folder, which seems to be compatible though a little buggy getting menu 3d to work, i gave up because the rest looks ok.
Cannot drag and drop menu.
Cannot preview edit home page. (works in gutenberg, but not classic)
Customize menu only showing widget tab.
I disabled all plugins and the issue remained.
I edit my sites daily so please fix this or let us know if we should go back to a previous version.
Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.