"All the controls in the edit screen should load only the data that is required to show the respective item"
I couldn't agree with you more :) ....but as per the video...that isn't the case.
Every selector loads itself up with a default set (20-50) of items to be selected when a new item opens....so if I create a new item, but NEVER use the selectors to pick content (either default media selectors or thunder generated selectors)...all that content is still coming down.
Moreover the controls are too "dumb" to share the same service calls. As you can see from the video I have a single image selector and a multi...BOTH call back to get lists of images AND lists of albums. So instead of 2 calls for 40 items, I have 4 calls for 80 items (when it should be 0 for 0 until I open the selector).
Now the images might be from <designers:ContentSelector trying to feed the product selector, but again, that control shouldn't be eagerly loading everything.
Know what I mean?