Program allows to delete rests in voices 2, 3 and 4 and creates confusion
1) Create new score, violin, enter four notes in voice 2
2) Delete the last three notes you entered. Result
3) Now delete the three rests. You'd say: "Impossible", but hey, they can be deleted. Result
Your score is now corrupt. Select the remaining note and try to make it a minim or a semibreve.
The variations on this are endless. Instead of deleting the last three notes in step 2), try deleting the first three and then the resulting rests.
I haven't tried 2.0 for a while, so perhaps it's not an issue there.