Regarding issue 58457 it would be also nice to have an API to set an error
message when customizer is in "invalid" state. Like 58457 it is needed by the
apisupport module. If there is any volunteer to fix this issue feel free to
Jano if you have or will have any opinions let me know. I would implement this
is simmilar manner to wizards dialogs.
Started. I'll attach a patch later and go through a fast-track review.
The patch with detailed description for the review is attached to issue 58457,
since these two are closely related. Look there for details. Thanks.
Thanks for review. Again see the issue 58457 for details.
Fixed. Commit log in the related issue 58457.