Calendar does not align properly

When I put a calendar and another component, let's say a textfield, on the same page and let them have the same left position, these two components are not properly rendered. The calendar component is does not have the same x position. See the screenshot below (left side: rendering in Firefox 2, right side: NetBeans 6.1 visual editor).


Both components have style="position: absolute; left: 96px;".
Is this a bug?

Regards, Stefan