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
/**
	 * If this style is used, a twistie will be used to render the expansion
	 * toggle.
	 */
	public static final int TWISTIE = 1 << 1;
	/**
	 * If this style is used, a tree node with either + or - signs will be used
	 * to render the expansion toggle.
	 */
	public static final int TREE_NODE = 1 << 2;
	/**
	 * If this style is used, the title text will be rendered as a hyperlink
	 * that can individually accept focus. Otherwise, it will still act like a
	 * hyperlink, but only the toggle control will accept focus.
	 */
	public static final int FOCUS_TITLE = 1 << 3;
	/**
	 * If this style is used, the client origin will be vertically aligned with
	 * the title text. Otherwise, it will start at x = 0.
	 */
	public static final int CLIENT_INDENT = 1 << 4;
	/**
	 * If this style is used, computed size of the composite will take the
	 * client width into consideration only in the expanded state. Otherwise,
	 * client width will always be taken into acount.
	 */
	public static final int COMPACT = 1 << 5;