Bug 156456 [Forms] widgets accept focus even though they can't do anything with it
Many of the widgets in the Forms library (Section, BusyIndicator, FormHeading) will accept keyboard focus even though they can't do anything with it. The impact is that when someone calls setFocus on a Form that contains a FormHeading at its top (which is quite common), keyboard focus ends up nowhere. Looking at the patterns in SWT, it appears that the correct protocol is for controls to return false from setFocus if they can't do anything with the focus so that the caller can try assigning focus somewhere else.
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/forms/widgets/ExpandableComposite.java
* @param listener
	 *            the listener to add
	 */
	public void addExpansionListener(IExpansionListener listener) {
		listeners.add(listener);
	}
	/**
	 * Removes the expansion listener.
	 * 
	 * @param listener
	 *            the listner to remove
	 */
	public void removeExpansionListener(IExpansionListener listener) {
		listeners.remove(listener);
	}
	/**
	 * If TITLE_BAR or SHORT_TITLE_BAR style is used, title bar decoration will
	 * be painted behind the text in this method. The default implementation
	 * does nothing - subclasses are responsible for rendering the title area.
	 * 
	 * @param e
	 *            the paint event
	 */
	protected void onPaint(PaintEvent e) {
	}
	/**
	 * Returns description control that will be placed under the title if
	 * present.
	 * 
	 * @return the description control or <samp>null </samp> if not used.