Bug 256656 [FieldAssist] cancel auto activation of proposal popup when caret moved
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
popup.getShell().addDisposeListener(new DisposeListener() {
						public void widgetDisposed(DisposeEvent event) {
							popup = null;
						}
					});
					internalPopupOpened();
					notifyPopupOpened();
				} else if (!autoActivated) {
					getControl().getDisplay().beep();
				}
			}
		}
	}
	/**
	 * Open the proposal popup and display the proposals provided by the
	 * proposal provider. This method returns immediately. That is, it does not
	 * wait for a proposal to be selected. This method is used by subclasses to
	 * explicitly invoke the opening of the popup. If there are no proposals to
	 * show, the popup will not open and a beep will be sounded.
	 */
	protected void openProposalPopup() {
		openProposalPopup(false);
	}
	/**
	 * Close the proposal popup without accepting a proposal. This method
	 * returns immediately, and has no effect if the proposal popup was not
	 * open. This method is used by subclasses to explicitly close the popup
	 * based on additional logic.
	 * 
	 * @since 3.3