Q:

Can I remove module info from Column "Extra" in Magento Admin_User Table?

I like my Magento database as clean as possible so whenever I uninstall an extension I also remove all data that was stored by this particular module from the database.
Now I noticed that there is some data stored in the extra column of the Admin_User Table too. It lists many old modules that I have removed in the past.
What is the purpose of this column and is it safe to remove the data that is related to exensions that are no longer installed?

A:

In theory you can set a lot of things in the extra column in a serialized format.
But the core uses this to remember the expanded/collapsed fieldsets in the system->configuration sections.
So each time you expand/collapse a config fieldset a request is made to admin/system_config/state/?container={fieldset_id}&value={1-expanded|0-collapsed}.
the container name and value are saved in the extra column (see method Mage_Adminhtml_System_ConfigController::stateAction) and is later retrieved in the method Mage_Adminhtml_Block_System_Config_Form_Fieldset::_getCollapseState so you will see the fieldset just like you left it (expanded|collapsed).
I strongly advice on keeping the column.
You can remove the data from it, but this means that the next time you visit a system->cofiguration section all fieldsets will be collapsed.

