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
public ILabelProvider getLabelProvider() {
		return labelProvider;
	}
	/**
	 * Return a boolean indicating whether the receiver is enabled.
	 * 
	 * @return <code>true</code> if the adapter is enabled, and
	 *         <code>false</code> if it is not.
	 */
	public boolean isEnabled() {
		return isEnabled;
	}
	/**
	 * Set the label provider that is used to show proposals. The lifecycle of
	 * the specified label provider is not managed by this adapter. Clients must
	 * dispose the label provider when it is no longer needed.
	 * 
	 * @param labelProvider
	 *            the (@link ILabelProvider} used to show proposals.
	 */
	public void setLabelProvider(ILabelProvider labelProvider) {
		this.labelProvider = labelProvider;
	}
	/**
	 * Return the proposal provider that provides content proposals given the
	 * current content of the field. A value of <code>null</code> indicates
	 * that there are no content proposals available for the field.
	 * 
	 * @return the {@link IContentProposalProvider} used to show proposals. May
	 *         be <code>null</code>.