Have you customized the dropdown or its renderers? If the ComboBox gets a
dataProvider change or a request to update the ComboBox's width/height it
will close again. It will also close if the ComboBox sees a mouseDown that
isn't in the ComboBox or its dropdown.
thanks, i found the problem. i was using a SuperPanel class, and when i update the sdk, start to fail. i changed it for a mdiWindow, inherit from flexlib