Hi Koen,
in SmartTree the system has control over the links and actions going on but in SmartEdit in just introduces some parts without changing the existing anchors.
I agree that several times when the system is not responding quickly enough the user feedback is not optimal. Maybe you could put some Javascript into SmartEdit mode that is bound to the click event of anchors (or whatever causes the document load) and displaying some "loading" label on the page.
Another field to improve this is to speed up the page load itself. Depending on the project and actions you perform on the page load there might be some room for improvement.
Best,
Hilmar Bunjes
erminas GmbH