The 'Fiddle' mode is used to tune a video mode for size, position, and
refresh rate.  The mode works in a loop, allowing you to make incremental
changes, and putting up a test display after you make a change.  For the
vast majority of situations, all you will need to adjust is vertical or
horizontal position, or to make the screen wider/narrower or taller/shorter.
The mode also gives you access to the very detailed timing numbers involved
in video mode generation, but in most cases, you will not need these.

When you done making changes to all of the modes you wish, select [s] to 
save the changes to the Xconfig template in the /tmp directory. NOTE: this 
does NOT save the Xconfig file! You will need to do select the [s]ave option 
when you get back to the '([v]iew, [s]ave, [t]une or [e]xit)' prompt.

It is possible that you may push the adjustments out of spec for your
monitor; if you do this, your monitor will go out of sync while the
test display is up (~5 seconds).  Because of the incremental nature of
the change, it is unlikely that any damage will occur; simply undo the
change you last made.

For detailed information on video timing configuration, refer to the
VideoModes.doc file included with your XFree86 distribution.
