Bug 26109 [Dialogs] Need a FormData version of the button sizing API
The button sizing API in Dialog assumes the developer wants a GridData. We should promote the FormData version in PathVariablesDialog to Dialog.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/Dialog.java
initializeDialogUnits(composite);
	
	
	dialogArea = createDialogArea(composite);
	buttonBar = createButtonBar(composite);
	
	
	return composite;
}
/**
 * Creates and returns the contents of the upper part 
 * of this dialog (above the button bar).
 * <p>
 * The <code>Dialog</code> implementation of this framework method
 * creates and returns a new <code>Composite</code> with
 * standard margins and spacing. 
 * </p>
 * <p>
 * The returned control's layout data must be an instance of 
 * <code>GridData</code>.
 * </p>
 * <p>
 * Subclasses must override this method but may call <code>super</code>
 * as in the following example:
 * </p>	
 * <pre>
 * 	Composite composite = (Composite)super.createDialogArea(parent);
 * 	//add controls to composite as necessary
 * 	return composite;