Bug 129214 [Field Assist] - Decorated Field attachments not centering images horizontally
DecoratedField is supposed to center decorations horizontally on each side. The current attachments are not doing so. Also consider whether grid would have been a better choice for internal implementation.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/DecoratedField.java
if (data == null)
			return;
		if (data.label != null) {
			data.label.setImage(decoration.getImage());
			
			
			if (data.label.getVisible() == true && hover != null) {
				showHoverText(decoration.getDescription(), data.label);
			}
		}
	}
	/*
	 * Set the visibility of the specified decoration data. This method does not
	 * change the visibility value stored in the decData, but instead consults
	 * it to determine how the visibility should be changed. This method is
	 * called any time visibility of a decoration might change, whether by
	 * client API or focus changes.
	 */
	private void setVisible(FieldDecorationData decData, boolean visible) {
		
		
		if (visible && decData.visible)
			decData.label.setVisible(true);
		else
			decData.label.setVisible(false);
	}
	/*
	 * Get the FieldDecorationData that corresponds to the given decoration.
	 */
	private FieldDecorationData getDecorationData(FieldDecoration dec) {