Bug 36446 [Contributions] widgets: Associating Actions with Buttons
Actions can be associated with Menu items , and tool bar items using MenuManager and ToolBarManager but there is not way to associate Action with a regular button and obtaining a reference to that button the closest thing is creating an ActionContributionItem with the desired action in its constructor , then filling the parent composite with ActionContributionItem.fill(Control parent) this creats the button , but it doesn't return a reference to that button , so for example i can't give it any layout data i suggest the ActionContributionItem.fill(Control parent) returns the created widget
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ActionContributionItem.java
*/
	private Menu holdMenu = null;
	private boolean menuCreatorCalled = false;
	
	/**
	 * The proxy menu is being shown, we better get the real menu.
	 * 
	 * @param proxy
	 *            the proxy menu
	 * @since 3.4
	 */
	private void handleShowProxy(Menu proxy) {
		proxy.removeListener(SWT.Show, getMenuCreatorListener());
		IMenuCreator mc = action.getMenuCreator();
		menuCreatorCalled  = true;
		if (mc == null) {
			return;
		}
		holdMenu = mc.getMenu(proxy.getParentMenu());
		if (holdMenu == null) {
			return;
		}
		copyMenu(holdMenu, proxy);
	}
	/**
	 * Create MenuItems in the proxy menu that can execute the real menu items
	 * if selected. Create proxy menus for any real item submenus.
	 * 
	 * @param realMenu
	 *            the real menu to copy from