Bug 148357 [Field Assist] - API - provide access for closing the proposal popup
I think that the field assist API needs more hooks to be customizable. For example : 1) There is no way to manually close/open the popup. Most of the times, this is the easier thing for a user to ask to implement his custom behaviour. 2) There is no way to intercept keystrokes/events directed to the field. 3) There is no way to control focus.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
* @return a constant indicating how an accepted proposal should affect the
	 *         control's content. Should be one of <code>PROPOSAL_INSERT</code>,
	 *         <code>PROPOSAL_REPLACE</code>, or <code>PROPOSAL_IGNORE</code>.
	 *         (Default is <code>PROPOSAL_INSERT</code>).
	 */
	public int getProposalAcceptanceStyle() {
		return proposalAcceptanceStyle;
	}
	/**
	 * Set the integer style that indicates how an accepted proposal affects the
	 * control's content.
	 * 
	 * @param acceptance
	 *            a constant indicating how an accepted proposal should affect
	 *            the control's content. Should be one of
	 *            <code>PROPOSAL_INSERT</code>, <code>PROPOSAL_REPLACE</code>,
	 *            or <code>PROPOSAL_IGNORE</code>
	 */
	public void setProposalAcceptanceStyle(int acceptance) {
		proposalAcceptanceStyle = acceptance;
	}
	/**
	 * Return the integer style that indicates how keystrokes affect the content
	 * of the proposal popup while it is open.
	 * 
	 * @return a constant indicating how keystrokes in the proposal popup affect
	 *         filtering of the proposals shown. <code>FILTER_NONE</code>
	 *         specifies that no filtering will occur in the content proposal
	 *         list as keys are typed. <code>FILTER_CUMULATIVE</code>
	 *         specifies that the content of the popup will be filtered by a