Example of issue: [https://en.wikipedia.org/w/index.php?title=User:Mdowdell/sandbox&oldid=600478437]
As can be seen in [https://en.wikipedia.org/w/index.php?title=User:Mdowdell/sandbox&oldid=600478437#mw-collapsible_mw-collapsed_sortable] the mw-collapsed sortable table hides the second row used for sorting. However, the collapsible table [https://en.wikipedia.org/w/index.php?title=User:Mdowdell/sandbox&oldid=600478437#collapsble_collapsed_sortable] show the second row when uncollapsing the table.
The problem is that mw-collapsible does not account for table rows placed in thead and tfoot, which are used by tablesorter.
It has the selector
$collapsible.find( '> tbody > tr' );
Version: 1.23.0
Severity: normal