steps to reproduce:
1. run lxterminal
2. run mc
3. disable mc panes by CTRL+O
4. select text on screen
5. paste it (shift+insert or by mouse)
text will be pasted with garbage "~0" at start and "~1" at end, something like ~0pasted text~1
it seems like trouble is in old x11-libs/vte-0.28.2-r208 which is used by lxterminal, similar tickets for other distros: https://bugs.launchpad.net/ubuntu/+source/vte/+bug/1350334 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=824359
fix: https://bugzilla.gnome.org/show_bug.cgi?id=729533 (from https://midnight-commander.org/ticket/3207 )
mc version: 4.8.18-r1
lxterminal versions: 0.1.11 and 0.2.0-r1
same trouble happens if lxterminal gtk3 flag is used (it uses vte 0.36.5 in that case).
x11-libs/vte-0.28.2-r208 is very old.
Perhaps some libraries on your system need to be rebuilt.
Is it fixed after updating the package?
No, it wasn't fixed. lxterminal seems to be depend on this old version.
When I added gtk3 flag to lxterminal - it was assembled with vte 0.36.5, but it has same trouble and after reboot it fails to start. So I reassembled it w/o gtk3.