Bug 223823 ControlExample: Select Listeners dialog opens behind menu bar
examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/controlexample/Tab.java
* <code>Tab</code> is the abstract superclass of every page
 * in the example's tab folder.  Each page in the tab folder
 * describes a control.
 *
 * A Tab itself is not a control but instead provides a
 * hierarchy with which to share code that is common to
 * every page in the folder.
 *
 * A typical page in a Tab contains a two column composite.
 * The left column contains the "Example" group.  The right
 * column contains "Control" group.  The "Control" group
 * contains controls that allow the user to interact with
 * the example control.  The "Control" group typically
 * contains a "Style", "Other" and "Size" group.  Subclasses
 * can override these defaults to augment a group or stop
 * a group from being created.
 */
abstract class Tab {
	Shell shell;
	Display display;
	
	
	Button borderButton, enabledButton, visibleButton, backgroundImageButton, popupMenuButton;
	Button preferredButton, tooSmallButton, smallButton, largeButton, fillHButton, fillVButton;
	
	Composite tabFolderPage;
	Group exampleGroup, controlGroup, listenersGroup, otherGroup, sizeGroup, styleGroup, colorGroup, backgroundModeGroup;
	
	final ControlExample instance;