A reference to the problem seen in bug$ 4066145:

All normal keys on the keyboard must deliver events.
This bug is not related to java.awt.TextField. It is saying that
KeyEvent's for cut/copy/paste are not created and passed to
KeyListeners on a Component. The reason cut/copy/paste works fine
for java.awt.TextField is that native code is handling it.
Since swing is not native, we need this bug to be fixed in AWT before
we are able to handle cut/copy/paste.

In motif look and feel, the middle mouse button copy/paste functionality should
also work.