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
proposalTable.showSelection();
			showProposalDescription(proposals[index].getDescription());
		}
		/**
		 * Opens this ContentProposalPopup. This method is extended in order to
		 * add the control listener when the popup is opened and to invoke the
		 * secondary popup if applicable.
		 * 
		 * @return the return code
		 * 
		 * @see org.eclipse.jface.window.Window#open()
		 */
		public int open() {
			int value = super.open();
			if (popupCloser == null) {
				popupCloser = new PopupCloserListener();
			}
			popupCloser.installListeners();
			IContentProposal p = getSelectedProposal();
			if (p != null) {
				showProposalDescription(p.getDescription());
			}
			return value;
		}
		/**
		 * Closes this popup. This method is extended to remove the control
		 * listener.
		 * 
		 * @return <code>true</code> if the window is (or was already) closed,
		 *         and <code>false</code> if it is still open