I'm on Linux, when I copy something from the editing window with the
mouse and I paste in the terminal pane inside geany with the central
mouse button, the terminal pane doesn't get the focus, pressing enter
makes the copied line(s) disappear in the editing window and doesn't
issue an enter in the terminal (this is the expected behaviour).
Geany 0.21 on latest Kubuntu Linux
Confirmed with Geany 1.23 (git >= 877b047)
Now fixed in Git, thanks for reporting.