Studio - icon 'Fields' doesn't work

Hi everyone,
in my suitecrm7.12 I can’t add a field in a module using Studio
When I click in the field icon there is no reaction, in any module.
After this click, no other Studio function runs: if click on ‘labels’ I need to type F5 to refresh the page end so labels appears on click.
But Field function never runs.
May somebody give me some suggestion?
Thank to all

more I find this in apache log
[Fri Nov 19 17:04:40.659126 2021] [php:error] [pid 1050] [client] PHP Fatal error: Uncaught Error: Attempt to modify property “vardefs” on null in /var/www/html/suitecrm/modules/ModuleBuilder/views/view.modulefields.php
:109\nStack trace:\n#0 /var/www/html/suitecrm/include/MVC/View/SugarView.php(210): ViewModulefields->display()\n#1 /var/www/html/suitecrm/include/MVC/Controller/SugarController.php(432): SugarView->process()\n#2 /var/www/html/suitecrm/incl
ude/MVC/Controller/SugarController.php(363): SugarController->processView()\n#3 /var/www/html/suitecrm/include/MVC/SugarApplication.php(101): SugarController->execute()\n#4 /var/www/html/suitecrm/index.php(52): SugarApplication->execute()
n#5 {main}\n thrown in /var/www/html/suitecrm/modules/ModuleBuilder/views/view.modulefields.php on line 109, referer:

Did you ever resolve this? I am brand new to SuiteCRM and cannot edit any fields with the same error.

This issues is related to file permissions sometimes. Make sure your web user was added to the config file and file permissions are correct in the system.

Check here for more info:

I’m running this in a docker container using the SuiteCRM admin user. I don’t know what you mean by “user added to the config file”.

Check this post for more info: