Bad text alignment in SWT Label

I am trying to do something that should be absolutely trivial, namely add a product version number to an RCP application's splash screen. So my code goes like this:

class ARMSplashHandler extends EclipseSplashHandler {
  private Font font; 
  private int heightInPx = 12;

  private开发者_运维百科 int fontHeightInPt(Display display, int heightInPx) {
    return 72 * heightInPx / display.getDPI().y;
  }

  @Override void init(Shell splash) {
    Product product = Platform.getProduct();
    Display display = splash.getDisplay();
    FontData fontData = splash.getFont.getFontData()[0];
    fontData.setHeight(fontHeightInPt(display, fontHeightInPx));
    font = new Font(display, fontData);
    splash.setBackgroundMode(SWT.INHERIT_DEFAULT);
    splash.setText(product.getName());
    splash.setFont(font);
    String version = "v"+product.getDefiningBundle().getHeaders().get("Bundle-Version");
    String versionLocString = product.getProperty("versionLocation");
    String versionColorString = product.getProperty("versionColor");
    Rectangle versionLoc = StringConverter.asRectangle(versionLocString, new Rectangle(405, 260, 45, 12));
    Color versionColor = new Color(display, StringConverter.asRGB(versionColorString, new RGB(193, 202, 212)));
    CLabel versionLabel = new CLabel(splash, SWT.CENTER | SWT.BORDER);
    versionLabel.setForeground(versionColor);
    versionLabel.setFont(font);
    versionLabel.setBounds(versionLoc);
    versionLabel.setText(version);

    splash.addDisposeListener(new DisposeListener {
      void widgetDisposed(DisposeEvent e) { 
        versionColor.dispose();
        font.dispose();
      }
    });
    super.init(splash);
  }

This works fine (except for a problem on Mac I'll ask about in a separate question; of course, the border is just for debugging):

But if I replace CLabel with Label, this happens:

It isn't centered, as expected. If I set alignment to RIGHT (which is what I really want), it disappears completely. Initially I thought the problem simply was that there isn't enough space, but increasing height of the rectangle doesn't fix the problem, and the width is certainly large enough:

Is this somehow expected behavior? Or an SWT bug (I certainly don't expect there to be one in something this basic)?