Bug 74163 [IDE] Tips and Tricks dialog; disable OK if no selection
OK should be disabled if one has not selected one entry in the list box above.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/TipsAndTricksAction.java
Shell shell = workbenchWindow.getShell();
        if (tipsAndTricksFeatures.size() == 0) {
            MessageDialog.openInformation(shell, IDEWorkbenchMessages.TipsAndTricksMessageDialog_title,
                    IDEWorkbenchMessages.TipsAndTricksMessageDialog_message);
            return;
        }
        AboutInfo[] features = new AboutInfo[tipsAndTricksFeatures.size()];
        tipsAndTricksFeatures.toArray(features);
        IProduct product = Platform.getProduct();
        FeatureSelectionDialog d = new FeatureSelectionDialog(shell, features,
                product == null ? null : product.getId(), IDEWorkbenchMessages.TipsAndTricksPageSelectionDialog_title,
                IDEWorkbenchMessages.TipsAndTricksPageSelectionDialog_message,
                IIDEHelpContextIds.TIPS_AND_TRICKS_PAGE_SELECTION_DIALOG);
        if (d.open() != Window.OK || d.getResult().length != 1) {
			return;
		}
        AboutInfo feature = (AboutInfo) d.getResult()[0];
        /**
         * Open the tips and trick help topic
         */
        if (feature != null) {
            final String href = feature.getTipsAndTricksHref();
            if (href != null) {
                BusyIndicator.showWhile(shell.getDisplay(), new Runnable() {
                    public void run() {
                        workbenchWindow.getWorkbench().getHelpSystem()
								.displayHelpResource(href);
                    }
                });
            } else {