If I drag a window in between two screens, half the window disappears. Is there a flag I can set from the command line or pref option somewhere to disable this?
My chrome window below is in the middle of my two monitors with the left half hidden.
have you tried system pref > mission control > and uncheck "displays have separate spaces"
Try going to System Preferences → Mission Control → and unchecking the option for Displays have separate Spaces.