JavaScript APIs in apex.region namespace for showing and hiding regions.
Declarative APIs override of jQuery show/hide functions.
Hide function should have an optional parameter for clearing values of APEX items inside the region.
APEX has, for a long time, had this odd thing where the item interface is used to show/hide regions. You can see this by looking at the dynamic_actions.js code.
I agree that the region interface should do its own/show hide.
The option to clear items inside the region is a little tricky. One issue is items don't have a clear method. Maybe they should. The other issue is that on the client side regions don't know what items they contain. People have asked for this as well.
Maybe to clear as in dynamic_actions.js _clear function? But it's still missing the get all items in region.
I made custom implementation for now, but it would be nice to have declarative API. :)
Support for a hierarchical/cascading capability from regions to subregions to items on Clear DAs and JS APIs would be useful.