/b> The number by which the scale factor is multiplied
resp. divided upon zooming in resp. out.</li>
    <li><b>Highlight color</b> Determines the color of highlights.</li>
    <li><b>Highlight duration</b> Determines the duration of temporary highlights.</li>
    <li><b>Annotation color</b> The color of annotations added by the program using
SVG color keywords or hexadecimal notation '#rrggbb'.</li>
    <li><b>Source editor</b> The program which is started to edit sources. '%1' is
replaced by the absolute 