Bug 132101 [Field Assist] does not work for characters that need AltGr, Ctrl+Alt or Strg+Alt
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
* this support is stable on all platforms.
	 */
	private void addControlListener(Control control) {
		if (DEBUG) {
			System.out
					.println("ContentProposalListener#installControlListener()"); 
		}
		if (controlListener != null) {
			return;
		}
		controlListener = new Listener() {
			public void handleEvent(Event e) {
				if (!isEnabled) {
					return;
				}
				switch (e.type) {
				case SWT.Traverse:
				case SWT.KeyDown:
					if (DEBUG) {
						dump("Traverse and KeyDown received by adapter", e); 
					}
					
					
					if (popup != null) {
						popup.getTargetControlListener().handleEvent(e);
						return;
					}
					
					if (e.type == SWT.Traverse) {
						return;