At present, the layout of the Lesson | Text Material doesn't ensure the SAVE button is always visible, even in full screen mode. This is on account of the scrolling for the page and the text content and due to the height setting for the text content.

The frustration come from the fact that because it is not visible it is easy for a user to ESC the page thinking the content is saved (as there is no warning of unsaved changes) only to find all the editing has been lost.

There is no reason that the SAVE button could not be positioned at the base of a fixed page height.

Following illustrates the problem.