contentLoad event is fired when ajax content is used (not my case) and select event will fire on change of tab selection and just before tabstrip collapses.

My need is that I have a tabstrip on top and a grid on the bottom of the screen. 
I need to know when the tabstrip has collapsed in order to resize the bottom grid to fill the remaining area, at the right time. 
Now I perform a resize after each select of tab with a timeout event (to wait for the potential animation delay of collapsing the tabscript).

I would also love to programmatically collapse or expand the tabstrip to give more space for the grid. The method I use now to achieve this will create problems in case you change the behavior of tabstrip in the future.

It also seems to me that the collapse and expand events should have been available from the very beginning when you first introduced the collapsible option.
It is an action that, currently, only the end user can activate, which will ultimately change the layout of the web page, and the developer will not know (at least with an easy to capture way).