Lexmark X646ef Menus And Messages Manual page 14

Button Button name
Back
Back
Back
Back
Using the MFP menus
Function or description
When the Back button is shaped like this, no other navigation is
possible from this screen except to go back. If any other choice is
made on the navigation bar, the screen closes.
For example, in Sample screen one all the selections for scanning
have been made. One of the preceding green buttons should be
touched. The only other button available is Back. Touch Back to return
to the previous screen, and all the settings for the scan job made on
Sample screen one are lost.
When the Back button is shaped like this, both forward and backward
navigation is possible from this screen, so there are other options
available on the screen besides selecting Back.
Using the LCD touch-screen buttons
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