Board Thread:Support Requests - Designing Your Wiki/@comment-30492097-20191106064457/@comment-9605025-20191106074854

Okay, first, let's deal with "closing" the tabs. Here is my proposed solution. For the template, use a dummy first tab and enclose the tabber in a give with the class "closable_tabber" so we can differentiate the closable ones from regular ones.  Then, we hide it with this CSS. This will make sure that the content of the dummy tab is always hidden and that the dummy tab is hidden while it is the active tab (i.e. while the tabs are "closed"). When the dummy tab is not active (i.e. another tab is open), the dummy tab will be shown and can be clicked on to "close" the current tab.
 * -|Close Tab=
 * -|Tab 1 = Tab 1 Content
 * -|Tab 2 = Tab 2 Content

As for the issue with long infoboxes, try changing the template to something like this: 

- Edit:

Changed suggested CSS to better accommodate your current styling.