Hi Baohua
AnaEx01 has exposed a weakness in the vis system. Specifically, AnaEx01 allows you to change geometry between runs. It turns out to be quite tricky to ensure that the vis system tracks these changes properly. Anyway, I have improved the vis system and now it does not crash and you see the changed geometry when you make the next run. This fix should appear in the next release - 11.1-beta - at the end of this month, June. If this is still bothering you I could send you a patch.
Thankyou for bringing this to our attention. It all makes for an improved Geant4 
John