Bug 73027 [Dialogs] Buttons are too high
I20040831 Buttons are no longer oval but have a rounded rectangle shape (see first screenshot). The second screenshot shows how buttons using the small system font should look like.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferencePage.java
if (oldValue != isValid) {
            
            if (getContainer() != null)
                getContainer().updateButtons();
            
            updateApplyButton();
        }
    }
    /**
     * Returns a string suitable for debugging purpose only.
     */
    public String toString() {
        return getTitle();
    }
    /**
     * Updates the enabled state of the Apply button to reflect whether 
     * this page is valid.
     */
    protected void updateApplyButton() {
        if (applyButton != null)
            applyButton.setEnabled(isValid());
    }
    /**
     * Creates a composite with a highlighted Note entry and a message text.
     * This is designed to take up the full width of the page.
     * 
     * @param font the font to use
     * @param composite the parent composite
     * @param title the title of the note
     * @param message the message for the note