paste incorrect in terminator after su

[Peter Baranyi <peter.baranyi@gmail.com>]

hi,

using Debian testing in KDE (Plasma) in the terminal 'terminator'
paste works correctly if I'm using my own user name but if I change to
root with su, both middle mouse click and right click->paste works
incorrectly. For example copying 'test' gets pasted as:

0~test1~

Why is this happening, how do I fix it?

thanks.