If we include tabpane content from more than one file (in this case, using the readfile shortcode), every tab pane gets the same HTML ID, and the tabs don't work correctly. (Click a tab in one pane, and the tab switches but not the content, but the content switches in another pane without switching its tab...)

Here's a PR preview showing this. (Associated PR is yugabyte/yugabyte-db#14425)

I don't think this is related to #1280, but maybe @deining or @chalin you have some ideas on how to fix this?