How to update the list of items in the SWT Combo box?

I have a U开发者_如何学PythonI with a Combo box. The list of items, which can be chosen, has to be refreshed every time the combo is about to open the list.

Is there any way - i.e. to add a listener which will inform UI that Combo is about to open?

Unfortunately I am not able to observe model to update the list when it changes.

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Unfortunatelly there is no such method for SWT Components. In Swing it would be easy with the help of the PopupMenuListener Interface.
A workaround I can think of would be to implement a MouseListener and a KeyboardListener (As Comboboxes can be opened by pressing 'space') so you can at least update your Combobox List when those two Events take place.