Problem with the display of "lecture mode"

Image 1:

Image 2:

Hello guys, for the porpouse of describing my problem I have adjunted two images.

Before, when I actived lecture mode my screen looked like Image 1, but now when I go to lecture mode my screen looks like Image 2.

I would like lecture mode to be displayed like it is shown on Image 1, but I haven't been able to do so.

Thank you for the help.