Sorry, I didn't make my question clear enough. my question is more about design, not my crash.
The reason to use another thread for network communication is that the thread is also doing some other task.

My question about design is should changed underneath data container inform controller and let controller change data model? or should changed data container inform data model directly? personally i prefer the latter. but the problem of the latter one is that the size of data model is controlled by the config setting in the gui, so data container has to get the info from controller if it controls data model, which against data containers' real functionality..

Thanks,