Trace reference bogging down

[GFBArchitect]

Usually the switching on of a trace reference or changing references is almost instant. But once in a while something happens to make the turning on or changing of the trace reference take about 30 seconds. And once it's on, zooming or panning also takes another 30 seconds. What causes this?

[Anonymous]

If you're referencing a view with different layers or view settings to your current view, or an auto-rebuild elevation or section, the reference will be slower to generate. Is this what you're experiencing?