Oxygen XML Editor uses the Apache Batik open source library to render SVG images. The Batik library only has partial support for SVG 1.2: http://xmlgraphics.apache.org/batik/dev/svg12.html.
For example, if you are using the Inkscape SVG editor, it is possible that it saves the SVG as 1.1 but it actually uses SVG 1.2 elements like flowRoot inside it. This means that the image will not be properly rendered inside the application.
SVG images shown in the Author visual editing mode are rendered as static images, without support for animations and Javascript.