Added support for track logos in the 'Generated image' background. Track logos come in light and dark format, choose between 'TrackLogo' and 'TrackLogoDark' in the image type. Note that track logo requires the (parent) widget DataSet to be set to "sessionstate" instead of any of the result data sets. The editor should warn you if you have the wrong DataSet / type combination.
Fixed a bug where the Theme Editor would not start