As you can see in this picture, iTerm is adding a kind of overlay cursor (plus this paper icon) above the terminal windows when I press Shift + any arrow key. It seems to be a text selection tool or something similar.
Since I have mapped Shift + left and Shift + right arrow in tmux to switch windows, I would like to deactivate this function of iTerm, but couldn't find anything in the settings. In earlier versions this did not appear. Currently I'm using Build 3.4.20200723-nightly.
Thanks for your help!