I the long run I think the coord cache should really be cache. It isn't
right now as we sometimes depend on certain values being present.
I have added some logic so it is easier to detect such errors. I see that during update, we rely on some coordinates to be there, when the cursor is drawn. Other than that, it seems that the usage of coordCache is pretty good. (I did not try with the user guide, because noone sent me one in the latest format, and I'm too lazy to install Python.)
To find all these places and replace them by sensible code is no 1.4 business as far as I am concerned, so at the moment, DEPM probably has to make sure that the cache is in no worse condition then before the DEPM call.
OK, I propose to add an "invalidate" method to the cache, and use this to flag whether a refresh is needed. The DEPM will set this flag. When I find time, I'll implement such a fix, unless someone else beats me to it.
Regards, Asger
