Task center iframes are only sized on load
Within the task center, iframes are used to include external content such as a TCE form for editing records as part of sys_action. These iframes have an onload attribute to set the height of the form, but this event handler could be improved.
Other iframes within the new backend are automatically resized when the browser window is resized (via Prototype event handlers) so the task center should get this same behavior.
(issue imported from #M7820)