In 2018 when coying and paste my objects disappear.
By copying again and paste they appear. Anyone?
Also:
By marking an object and doubleclick rotate and rotate say 90° the object makes the same....disappear.
There remains a "ghost", an orange line when you pass it with the cursor and its possible to copy, delete it and paste it again.
Then it appears.
Work on mac Sierra 10.12.6
Rolle