system_usermanager.php: Group selections not retained when an input error occurs
When doing such a simple thing as adding a ssh key, I completely deprived myself of access to webgui or ssh and was able to restore it only with the help of another administrator.
1. open /system_usermanager.php?act=edit&userid= myuserid
2. make some changes AND make a mistake in filling in the fields (different content of Password and PswdConfirmation fields for example) and press SAVE.
then page will be refreshed with error message on the top; but all my groups have moved from right list "Member of..." to left "Not member of". It's easy not to notice this.
3. fill fields with no mistakes and press SAVE
4. Done! All that you can see under your account now is No page assigned to this user! Click here to logout error page. SSH login is also no longer possible.
Reproduced on Firefox 62Dev, Chrome 69Dev without any script blocker