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 client
	 *            the client that will be expanded or collapsed
	 */
	public void setClient(Control client) {
		Assert.isTrue(client != null && client.getParent().equals(this));
		this.client = client;
	}
	/**
	 * Returns the current expandable client.
	 * 
	 * @return the client control
	 */
	public Control getClient() {
		return client;
	}
	/**
	 * Sets the title of the expandable composite. The title will act as a
	 * hyperlink and activating it will toggle the client between expanded and
	 * collapsed state.
	 * 
	 * @param title
	 *            the new title string
	 * @see #getText()
	 */
	public void setText(String title) {
		if (textLabel instanceof Label)
			((Label) textLabel).setText(title);
		else if (textLabel instanceof Hyperlink)
			((Hyperlink) textLabel).setText(title);
	}