Bug 147377 [Field Assist] - open proposal popup should close when there are no valid proposals left
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
* supplied {@link IContentProposalProvider}.
	 * 
	 * @param filterStyle
	 *            a constant indicating how keystrokes received in the proposal 
	 *            popup affect filtering of the proposals shown.
	 *            <code>FILTER_NONE</code> specifies that no automatic filtering 
	 *            of the content proposal list will occur as keys are typed in the
	 *            popup.
	 *            <code>FILTER_CUMULATIVE</code> specifies that the content of
	 *            the popup will be filtered by a string containing all the
	 *            characters typed since the popup has been open.
	 *            <code>FILTER_CHARACTER</code> specifies that the content of the
	 *            popup will be filtered by the most recently typed character.
	 */
	public void setFilterStyle(int filterStyle) {
		this.filterStyle = filterStyle;
	}
	/**
	 * Return the size, in pixels, of the content proposal popup.
	 * 
	 * @return a Point specifying the last width and height, in pixels, of the
	 *         content proposal popup.
	 */
	public Point getPopupSize() {
		return popupSize;
	}
	/**
	 * Set the size, in pixels, of the content proposal popup. This size will be
	 * used the next time the content proposal popup is opened.
	 *