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
public void run() {
						update(e.getProperty());
					}
				});
			}
		}
	}
	/**
	 * Compares this action contribution item with another object. Two action
	 * contribution items are equal if they refer to the identical Action.
	 */
	public boolean equals(Object o) {
		if (!(o instanceof ActionContributionItem)) {
			return false;
		}
		return action.equals(((ActionContributionItem) o).action);
	}
	/**
	 * The <code>ActionContributionItem</code> implementation of this
	 * <code>IContributionItem</code> method creates an SWT
	 * <code>Button</code> for the action using the action's style. If the
	 * action's checked property has been set, the button is created and primed
	 * to the value of the checked property.
	 */
	public void fill(Composite parent) {
		if (widget == null && parent != null) {
			int flags = SWT.PUSH;
			if (action != null) {
				if (action.getStyle() == IAction.AS_CHECK_BOX) {
					flags = SWT.TOGGLE;