Remove unnecessary Apply and close button in property dialog

This commit retains only the cancel button and eliminates the Apply and
close button in the property dialog which is unnecessary in the current
context there. There is only a description provided in the property
dialog and there is no event that needs an apply option.

Fixes: eclipse-equinox/p2#1049

Author: elsazac

bundles/org.eclipse.ui.workbench/eclipseui/org/eclipse/ui/internal/dialogs/PropertyDialog.java

@@ -17,13 +17,15 @@
 
 import java.util.Iterator;
 import org.eclipse.core.runtime.Adapters;
+import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.preference.IPreferenceNode;
 import org.eclipse.jface.preference.PreferenceManager;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.osgi.util.NLS;
+import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.PlatformUI;
@@ -90,6 +92,20 @@ public static PropertyDialog createDialogOn(Shell shell, final String propertyPa
 		return propertyDialog;
 
 	}
+	
+	@Override
+	protected void buttonPressed(int buttonId) {
+		if (buttonId == IDialogConstants.CLOSE_ID) {
+			cancelPressed();
+			return;
+		}
+		super.buttonPressed(buttonId);
+	}
+
+	@Override
+	protected void createButtonsForButtonBar(Composite parent) {
+		createButton(parent, IDialogConstants.CLOSE_ID, IDialogConstants.CLOSE_LABEL, true);
+	}
 
 	@Override
 	protected void addButtonsToHelpControl(Control control) {
@@ -162,6 +178,11 @@ protected String getSelectedNodePreference() {
 		return lastPropertyId;
 	}
 
+	@Override
+	public void updateButtons() {
+		// This function is overridden to remove the Apply and close button
+	}
+
 	/**
 	 * Get the name of the selected item preference
 	 */