Erratic appearance of the report interface

[hgeorgsch]

The report interface often comes up with an unstyled form, instead of the familiar moodle layout. This comes up unpredictably, but it may seem as if it happens more often if the user have other pages open in the same session, where moodle is slow to respond (such as deployment of STACK quesftions).

There seems to be locks in place, preventing the same session from running more than one resource intensive process on the server. This is probably put in place for good reasons, and may possibly explain this problem. However, it does not happen to other pages I have seen.

It would be better to show an informative error message than the wrongly formatted form.