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
}
	}
	/*
	 * The target control lost focus. Any decorations that should show only when
	 * they have the focus should be hidden here.
	 */
	private void controlFocusLost() {
		for (int i = 0; i < DECORATION_SLOTS; i++) {
			if (decDatas[i] != null && decDatas[i].showOnFocus)
				setVisible(decDatas[i], false);
		}
	}
	/**
	 * Show the specified decoration. This message has no effect if the
	 * decoration is already showing, or was not already added to the field
	 * using <code>addFieldDecoration</code>.
	 * 
	 * @param decoration
	 *            the decoration to be shown.
	 */
	public void showDecoration(FieldDecoration decoration) {
		FieldDecorationData data = getDecorationData(decoration);
		if (data == null)
			return;
		
		data.visible = true;
		
		
		if (!data.showOnFocus || control.isFocusControl())
			setVisible(data, true);