Bug 262022 [FieldAssist] ContentProposalAdapter.recomputeProposals might throw a NPE
When a control using content proposal gets disposed during usage the recomputeProposals() method might throw a NPE. This is caused by getting "allProposals" using a call to getProposals() which is allowed to return null. When using allProposals.length this will crash. I'm not sure if the simple solution if ((allProposals == null) || (allProposals.length == 0) { proposals = new IContentProposal[0]; close(); } else { // cont. will work or if the popup will have problems with a disposed control.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ContentProposalAdapter.java
* proposal provider. If there are no proposals to be shown, do not show the
	 * popup. This method returns immediately. That is, it does not wait for the
	 * popup to open or a proposal to be selected.
	 * 
	 * @param autoActivated
	 *            a boolean indicating whether the popup was autoactivated. If
	 *            false, a beep will sound when no proposals can be shown.
	 */
	private void openProposalPopup(boolean autoActivated) {
		if (isValid()) {
			if (popup == null) {
				
				recordCursorPosition(); 
				IContentProposal[] proposals = getProposals();
				if (proposals.length > 0) {
					if (DEBUG) {
						System.out.println("POPUP OPENED BY PRECEDING EVENT"); 
					}
					recordCursorPosition();
					popup = new ContentProposalPopup(null, proposals);
					popup.open();
					popup.getShell().addDisposeListener(new DisposeListener() {
						public void widgetDisposed(DisposeEvent event) {
							popup = null;
						}
					});
					internalPopupOpened();
					notifyPopupOpened();
				} else if (!autoActivated) {
					getControl().getDisplay().beep();