Steps to Reproduce

http://zkfiddle.org/sample/k29vpf/3-multiple-RM-when-clearing-model
run fiddle.
Select hold 500 items.
Click button to clear the model.

Actual Result

Model is cleared, 500 "rm" commands are sent to the client.

Expected Result

Model is cleared, a single clear model command could be sent instead.

Workaround

Use ListModelList instead of ArrayList as model