Linux version 1.2.1.
Selected (orange ones) tracks thickness is always 1px, regardless of the Layer Properties settings.
Should be straightforward to fix it, setting it to the thickness of the Layer property the track is in.
Alternatively one could create a controlable thickness setting for the selected track regardless of the Layer, but I'll go for the first solution.
Fix available in https://github.com/rnorris/viking/commits/StagingPatches
This will be promoted into the git master in a week or two.