See https://bugs.jquery.com/ticket/9841. In our case, the OutputArea was triggering a ‘resize’ event on its element, which was bubbling up and causing this handler to execute every time an output was appended. This was a pretty big drain on output areas that quickly changed (like for interact widgets), presumably since this function involves a DOM read to get heights.
Min RK
Jason Grout
Jonathan Frederic
Matthias Bussonnier