This is a new bug to 17.2.x. (Linux) When I open the marker edit pop-up window by pressing "M" on a marker, the window doesn't have keyboard focus, and I have to click into it with the mouse to edit anything. This is a change from 17.1 which used to give focus to the window on opening.
Presumably this is related to fixing the issue noted here, where you couldn't close the marker pop-up with the keyboard:
viewtopic.php?f=33&t=144138