When editing a wiki page the default value for the tags input box is empty even if there are tags. Saving the page will cause the tags to be deleted.

Replication steps:

1. Log in as teacher/admin.
2. Create a Wiki activity.
3. Add an initial page including multiple "Other" tags, separated by commas.
4. Save the page.
5. Click "Edit" in the tabs at the top.

Expected result: The previously added tags should appear in the editing form.

Actual result: No tags appear and the following error appears for each missing tag...

Warning: Invalid argument supplied for foreach() in D:\xampp\htdocs\master_integration\lib\form\tags.php on line 216