MIDI notes disappear when copy-pasting from two different tracks

[Denys]

Before I transfer MIDI data from Reaper to Sibelius, I usually quantize a lot and separate left and right hand parts into two tracks.


The first copy-paste shows how I proceed when copying from one track to the other. The second one shows how some data from one track doesn't go to the second track. The third time is the same behavior but with the right-clic commands.


I'm using V6.15