My application allows the user to move the cursor a long a two-dimensional color plot. Updating in response to the cursor, it generates two other graphs, each one dimensional. A fairly compute intensive operation.
So I have a problem: on slower machines, the process lags considerably and the graphs may continue updating for several seconds after the user has finished moving the cursor. To help with this, I pulled out the building of graphs into a separate loop, with a Notifier linking the main event loop to the graph building loop. This helps: if things get too far behind, the Notifier remembers only the most recent notification, and the graph building loop acts only on that.
Well, that fixed it mostly. But I still get four or five graph updates after I stop dragging the cursor. Since the information couldn't possibly be stored in the notifier, it must be getting stored in the event queue. Which says that the event loop is not steadily getting priority over the graph building loop.
The documentation says that you can set the relative priorities of loops by putting longer and shorter Wait operations in them. But what about an event loop? It has no Wait operation, it is timed by the Event structure itself.
