I have a VerticalLayoutContainer that sinks Event.ONMOUSEMOVE events and when items are dragged around an AbsolutePanel which is contained in the VerticalLayoutContainer I need to update the UI.
The problem is that unless draggable.setUseProxy(false) is called most ONMOUSEMOVE events do not get fired, a (very) few events do get fired but that makes the setUseProxy(true) mode, which is the default, unusable because the behavior is completely unpredictable. With setUseProxy set to false then the event fires as expected.
To help us debug your exact scenario, could you provide us with your test case (preferably implementing EntryPoint)? This will help to ensure that there is no difference between what you're describing and our efforts to reproduce the issue.