Having a tree where each item has a popup menu, if you first create the tree with an empty model and then an event changes the model so that the tree is not empty anymore, the popup menu do not raises when you right click on the item (it appears only if you right click on the small arrow on the left side of the item).

You can use this fiddle to replicate the problem : http://zkfiddle.org/sample/gclbt6/10-Tree-and-Popup-Menu

The problem affects only zk 7.0.0 : it works ok with ZK 6.5.3

Reproduced with both chrome and firefox.