I'm testing a client's site to update from Joomla 3 to Joomla 4, using T3 Framework and the T3 bs3 Blank template. I wanted to make changes to the custom.css file but for some reason the menu buttons for Save, Save and Close, and Close don't work at all; they change colour but nothing happens - they just hang. I tried saving a file in the T3 Blank template and got the same problem - those buttons just hang.
I tried going into the Cassiopeia template and was able to save one of those files, no problem, so it must be something to do with the T3 templates.
So: I updated the T3_bs3 template file manually from a fresh download (from version 2.2.9 to 3.0.2), as well as the T3 Plugin (which was already up to date), and it said both succeeded, but the problem remains.
When I turn on Global Configuration > Error Reporting, I get a bunch of what look like PHP warnings. (FYI: I'm using PHP 8.0.29 and Joomla 4.3.2.)
_Warning: Undefined array key "id" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/base.php on line 12
Warning: Undefined array key "doTask" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/standard.php on line 12
Warning: Undefined array key "id" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/base.php on line 12
Warning: Undefined array key "doTask" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/standard.php on line 12
Warning: Undefined array key "id" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/base.php on line 12
Warning: Undefined array key "id" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/base.php on line 12
Warning: Undefined array key "id" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/base.php on line 12
Warning: Undefined array key "doTask" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/standard.php on line 12
Warning: Undefined array key "id" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/base.php on line 12
Warning: Undefined array key "style" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/separator.php on line 13
Warning: Undefined array key "id" in .../plugins/system/t3/base-bs3/html/layouts/joomla/toolbar/base.php on line 12_
Perhaps these warnings are the problem? If so, I don't know how to fix them. Please help! Many thanks in advance.