Insert > Horizontal Lines (Mathematica Menu Item)

Horizontal Lines opens a submenu to insert a line of the specified thickness above or below the selected cell.

Graphics > Operations > Move to Back (Mathematica Menu Item)

Move to Back moves selected graphics objects to the back of the display.

Graphics > Operations > Move to Front (Mathematica Menu Item)

Move to Front moves selected graphics objects to the front of the display.

File > Printing Settings > Page Setup... (Mathematica Menu Item)

Page Setup controls the size and shape of the pages to be printed.

Help > Register this Mathematica... (Mathematica Menu Item)

Online Registration opens the Mathematica registration website.

Cell > Cell Tags > Show Cell Tags (Mathematica Menu Item)

Show Cell Tags toggles the display of cell tags in a notebook.

Show Debugger Tools Window toggles the display of the Debugger Tools window on or off.

Show Stack Window toggles the display of the evaluation stack window on or off.

[Right-click] > Speak Selection (Mathematica Menu Item)

Speak Selection speaks the contents of a single selected cell.

Evaluation > Debugger Controls > Step (Mathematica Menu Item)

Step makes the debugger stop at the beginning of the next expression.