If the window is mostly off-screen ..
a) off the lower right corner of the screen: You must grab it by the bar AFTER the (useless, unremovable) CREATE button on a mouse left click.
b) off the lower left corner of the screen: You must grab it by the bar BEFORE the ? button (more useless, unremovable guff prior to the window controls)

The title bar regions outside of the unused centre can not be used to move the window.