I'm still not online very often, but I found time to learn a bit Javascript. And that is the result:
If you doubleclick on a track- or vehicle-checkbox in the navi frame it will become checked and all other checkboxes will become unchecked.
Except if the doubleclicked checkbox already was the only checked box. In that case all checkboxes become checked.
Hmm, ok, you will find out anyways, so I can tell you right now just as well: There is an exception to the exception: if the doubleclicked box was an original track, only the original tracks will become checked.
I'm sure this will save you some clicks in the future. Try it out!
If you doubleclick on a track- or vehicle-checkbox in the navi frame it will become checked and all other checkboxes will become unchecked.
Except if the doubleclicked checkbox already was the only checked box. In that case all checkboxes become checked.
Hmm, ok, you will find out anyways, so I can tell you right now just as well: There is an exception to the exception: if the doubleclicked box was an original track, only the original tracks will become checked.
I'm sure this will save you some clicks in the future. Try it out!