Look very carefully in the extreme top right of the screen grab you have submitted. I can see a vertical row of 6 dots. To me this indicates ANOTHER docked window. Now, the Media Generator Menu may have got itself "squished" into that portion of your screen? What you can do is EITHER grab those dots and bring it front and centre, giving the options to re-size and reposition OR you could reduce the size of the docked window/tabbed section to bring this "other" widow into view. This "other" window may well be your Generated Media Menu.