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/internal/forms/widgets/BusyIndicator.java
&& !offScreenImage.isDisposed())
							offScreenImage.dispose();
						if (offScreenImageGC != null
								&& !offScreenImageGC.isDisposed())
							offScreenImageGC.dispose();
					}
				});
				clearImages();
			}
			if (busyThread == null)
				display.syncExec(new Runnable() {
					public void run() {
						animationImage = null;
						if (!isDisposed())
							redraw();
					}
				});
		}
		
		public void setStop(boolean stop) {
			this.stop = stop;
		}
	}
	private static final int MARGIN = 0;	
	private static final int IMAGE_COUNT = 8;
	private static final int MILLISECONDS_OF_DELAY = 180; 
	private Image[] imageCache;
	protected Image image;
	protected Image animationImage;
	protected BusyThread busyThread;