Bug 164529 [FieldAssist] Provide the ability to listen to start and end field assist events
In the previous content assist functionality, an ICompletionListener could be specified to listen to the following events: public void assistSessionEnded(ContentAssistEvent event) public void assistSessionStarted(ContentAssistEvent event) The equivalent listener, IContentProposalListener, does not listen to those two events. PDE needs to know when an assist session is ended in order to reset the state it maintains for custom filtering of java type results. The current event does not handle the case where the user ends the content assist without selecting a proposal: public void proposalAccepted(IContentProposal proposal);
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
/*
		 * Creates the content area for the proposal popup. This creates a table
		 * and places it inside the composite. The table will contain a list of
		 * all the proposals.
		 * 
		 * @param parent The parent composite to contain the dialog area; must
		 * not be <code>null</code>.
		 */
		protected final Control createDialogArea(final Composite parent) {
			
			if (USE_VIRTUAL) {
				proposalTable = new Table(parent, SWT.H_SCROLL | SWT.V_SCROLL
						| SWT.VIRTUAL);
				Listener listener = new Listener() {
					public void handleEvent(Event event) {
						handleSetData(event);
					}
				};
				proposalTable.addListener(SWT.SetData, listener);
			} else {
				proposalTable = new Table(parent, SWT.H_SCROLL | SWT.V_SCROLL);
			}
			
			recomputeProposals(filterText);
			proposalTable.setHeaderVisible(false);
			proposalTable.addSelectionListener(new SelectionListener() {
				public void widgetSelected(SelectionEvent e) {
					
					
					if (e.item == null) {