Board Thread:Support Requests - Getting Technical/@comment-33083465-20171005011530/@comment-9605025-20171009195704

Go to Special:Preferences and select the "Editing" tab. Under "Editing experience", click the drop-down next to "Preferred editor" and select "Source editor". Then scroll to the bottom of the page and click "Save". Next, edit [ Template:Parent Tab Template]. Currently, the template section looks like this:

'''NOTE: It looks like you are missing some closing tags and brackets in your non-template section. This may cause issues later.'''

Then replace all instances of the first set of markup I showed you in with the second set of markup.

By the way, it looks like your template is setup for up to 8 "tabs".