Today I got annoyed using eclipse code completion to add a KeyAdapter on a SWT component. Instead of adding the SWT KeyAdapter (since it's a SWT widget), eclipse suggests the AWT KeyAdapter before the SWT KeyAdapter. The result of this is that I often choose the wrong one.
Same thing with other classes like KeyListener, MouseListener...
So I was looking for a solution, eclipse should ignore the java.awt package.
I have not found a way to handle this for the whole workspace using preferences.
I now exclude the java.awt package in all my UI bundles from their Java Build Path.
Maybe you have had the same "trouble" and never thought about getting rid of it :-)