Use joystick mode
A modal layer is an absolute positioned element usually opaque or translucent with a z-index greater than the elements being covered and covering the complete area of the web page. Modal layers are useful to build "modal elements" simulating desktop modal windows in web.
The modal layer is added as a direct child of the visual root element (<body> in HTML <svg> in SVG) added in the end. This way any mouse click is not dispatched to any covered element in the document.
By default there is no markup content contained by the modal layer, new markup can be added "on top" of the modal layer specifing a greater z-index. This new markup should be added in the end of the visual root element.
In pure SVG documents behavior is very similar to X/HTML, the main difference is z-index is ignored in SVG because z-order in SVG follows the rendering order, this order coincides with document order. More info.