Where to start if I want to create a custom combo with popup tree viewer

The normal SWT combo can only show a popup list when you clic开发者_JAVA百科k the triangle button. For some reason, I want to orgnize the selectable items in tree instead of list. It turns out I've to customize the combo to realize this. Can anyone tell me where should I begin with?

Take a look at project Nebula. It is a collection of more advanced SWT components. It does not have a tree combo, but it does have a table combo. Perhaps it will fit your needs. Even if it doesn't, you can read the source and get a good idea on how to implement it, perhaps use it as a starting point.

You can find more SWT custom widgets floating around (GIYF).