title: javafx background image position outside of hbox
body: <p>The problem occurs when <code>-fx_background-position:0 -40</code> is set either by a loaded <em>style.css</em> or in code via an action handler. 
  In my example the background image is set on an <code>hbox</code> width one cell. When adjusting position the background image, the image moves outside of the limits/borders of the <code>hbox</code>, up in this case, and covers an area over the position of the <code>hbox</code>. In my case it covers action buttons so they don't fire. 
  How to not show the part of the background image that is outside of <code>hbox</code>?</p>