BOTH are visible, right? Image above shows only one visable.
BOTH visible.
The little eye icon shows an open eye ... with NO SLASH through the icon.
I see, however, something that says 'Error' in that screen shot.
However, the error generated indicates one of two things I can think of without seeing it myself:
1. the DB user doesn't have some access/permissions it needs to create data in the tables for the new assignment.
mysql> select * from user where user=root;
In example, 'root' above is the DB user found in the config.php file of your site.
That user needs to have access rights to do all things related to the Moodle DB.
Can do the same types of things in phpmyadmin.
or, 2. the 'mdl_assign' tables don't exist ... which is strange cause they are supposed to be there.
Did you un-install any mod?
Got something to use to query the DB?
mysql> show tables like 'mdl_assign%';
Will render all the tables related to assignment (the old mod) and assign (the new mod):
mysql> show tables like 'mdl_assign%';
+----------------------------------+
| Tables_in_moodle26 (mdl_assign%) |
+----------------------------------+
| mdl_assign |
| mdl_assign_grades |
| mdl_assign_plugin_config |
| mdl_assign_submission |
| mdl_assign_user_flags |
| mdl_assign_user_mapping |
| mdl_assignfeedback_comments |
| mdl_assignfeedback_editpdf_annot |
| mdl_assignfeedback_editpdf_cmnt |
| mdl_assignfeedback_editpdf_quick |
| mdl_assignfeedback_file |
| mdl_assignment |
| mdl_assignment_submissions |
| mdl_assignsubmission_file |
| mdl_assignsubmission_onlinetext |
+----------------------------------+
To re-install the 'assign' mod, download a zip of the moodle code for your version (2.6.x).
Unzip the zip locally.
In the unzipped archive, look in mod for a folder called 'assign' and zip that folder.
Then, upload the newly created zip to /pathtomoodlecode/mod/
and unzip it there.
Change ownerships/permissions to match other folders/files found in moodlecode.
Go to site and login as admin.
Site Admin Menu
Notifications.
Let's see if that takes away the 'Error' in the listing of mods.
If you are remotely hosted and don't have command line access or some tool to see files in moodlecode, you might have to rely on server support.
Ken