One of the terminal emulators I use, possibly the one that comes with lxqt that Lubuntu installs by default, pops up an "are you sure?" window showing exactly w

One of the terminal emulators I use, possibly the one that comes with lxqt that Lubuntu installs by default, pops up an "are you sure?" window showing exactly what I am about to paste whenever I middle-click-paste anything with a new-line. It can be disabled, but I found I quite like that extra check and would not mind if other applications did that.