Explanation

CTRL+SHIFT+F6 Switch to the previous workbook window

Additional information:

CTRL+F7 When a workbook window is not maximized, perform the Move command 

CTRL+F6 When more than one workbook window is open, switch to the next workbook window.

Ctrl+Shift+F12 Prints the current worksheet.

 F7 Displays the Spelling dialog box to check spelling