In plasma-login-manager 6.5.91, when the login screen is idle with the password entry field active (as is most commonly the case), most keypresses do not wake the screen, but *do* take effect. Typing a character causes it to appear in the password field (though you can't see it yet). Hitting tab changes the focus to the 'display password' eye icon (though, again, you can't see it yet). The only keypress that actually transitions the visible screen to its active state is enter - but that keypress alone does *not* take effect. It wakes the screen, but does not submit whatever password you typed while it was idle; you have to hit it again to submit the password. The behavior changes a little depending on what item on screen is active when the screen goes idle (or what element you make active with the tab key while the screen is idle). For e.g., if the 'Other' button is active, hitting enter takes effect but does *not* wake the screen; hitting 'esc' now wakes the screen and shows the username field, indicating that 'Other' did indeed take effect. I'll test soon to see if this is new in 6.5.91 or not, but even if not, it's certainly much more *visible* with the new default 10 second idle timeout.