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
* layout is incremented.  Subclasses may override.
 * </p>
 *
 * @param parent the parent composite
 * @param id the id of the button (see
 *  <code>IDialogConstants.*_ID</code> constants 
 *  for standard dialog button ids)
 * @param label the label from the button
 * @param defaultButton <code>true</code> if the button is to be the
 *   default button, and <code>false</code> otherwise
 * 
 * @return the new button
 * 
 * @see getCancelButton
 * @see getOKButton
 */
protected Button createButton(Composite parent, int id, String label, boolean defaultButton) {
	
	((GridLayout)parent.getLayout()).numColumns++;
	Button button = new Button(parent, SWT.PUSH);
	button.setText(label);
	
	button.setData(new Integer(id));
	button.addSelectionListener(new SelectionAdapter() {
		public void widgetSelected(SelectionEvent event) {
			buttonPressed(((Integer) event.widget.getData()).intValue());
		}
	});
	if (defaultButton) {
		Shell shell = parent.getShell();