improve form error detection

reason: errors signaled with only a little red ! sign beside a field
were not detected (such as admin user form)
Revert "add waiting loop for choosing admin user"

This reverts commit a25f2e4dda1a68ac7ee8d64827f6234343f7ea3c.

reason: there should be no need for a waiting loop here. The absence
may be due to an incomplete error detection (fixed in the previous
commit)