One real oddity is that in your setupPortrayals method you are creating a new FastObjectGridPortrayal2D, then attaching it.  But you didn't get rid of (detatch) the old one.  Furthermore you create a new Display and register it but don't get rid of the original display!

This is gonna cause a lot of issues.

You shouldn't have any display code in setupPortrayals at all.  That should be only in init.  It's done once and that's it.

You shouldn't make a new FastObjectGridPortrayal2D in setupPortrayals and attach it unless you've first detached the original one.  I suggest instead just taking the original one and setting it to the new field.