Select with mouse doesn't select (double)barline: why?

All in the tilte +gif:
usage: I often must copy passages for educational exercises and tranposition licks

Have you tried CTRL/CMD + Clicking the double-barline to add it to your selection?

Thanks but I want use the mouse to select. My exemple is just to illustrate my question! I have a lot of double bar line and don’t want to add one by one

We decided that Dorico should not select normal barlines in marquee selections, because then it would be too easy to accidentally delete barlines and change the rhythmic structure of the music. However, I agree it would be good if special barlines could be included in marquee selections, and we’ll change this in future.