Flex Drag and Drop is broken

I am trying for  a week to make draging from a List or Tree into an HTMl work, but the framework is so broekn, soem events will nver fire like the dragdrop event, calling acceptDragDrop has no effect and later I noticed that mouseUp event are not fireing also(it works sometime in a test application so I fear is a layout thing, I read that  drops will not work on some containers but this seems to be a very stupid limitation.