Hi,
The tabs shortcode example has a typo in it (the unnecessary underline in the closing [/thead]). The correct example should read:
[tabs]
[thead]
[tab href="#tab1" title="First tab"]
[tab href="#tab2" title="Second Tab"]
[/thead][tabgroup]
[tabinner id="tab1" class="active"]First tab content[/tabinner]
[tabinner id="tab2"]Second tab content[/tabinner]
[/tabgroup]
[/tabs]
We’ll revise the documentation to correct and improve it.