Steps to Reproduce: case1

1. run the zul in ZK-5551
2. add 2 items
3. click "render all"

Current Result

only the 1st item rendered

Expected Result

2 items rendered

Steps to Reproduce: case2

1. add 1 item
2. click "render all"
3. add 1 item
4. click "render all"

Current Result

no item rendered

Expected Result

2 items rendered