Hello. Thank you for contacting the Toolset support.
Well - When you try to create tabs using tabs cell and when you try to add a new tabs cell the tabs popup will allow you to select the option how you want to display the tabs. Please check following screenshot:
=> hidden link
You should select your desired option and try to resolve your issue.
Once you have done that then you go to Toolset -> Settings -> General -> Bootstrap Layouts and select the option "Toolset should load Bootstrap 3.0" after which your tabs should start showing.
Thanks. The tabs are working now but I get the following error when I try to edit a layout.
Fatal error: Call to undefined method WPV_Editor_addon::render_shortcodes_wrapper_dialogs() in /home/superblo/public_html/trooptravel.com/wp-content/plugins/wp-views/embedded/inc/classes/wpv-shortcode-generator.php on line 76
As we were able to resolve the initial issue of the Layouts Tab not working on Avada, it would be best to open a new ticket to handle this second request in that ticket.