Did you try Send Backward instead of Send to Back? When you moved the line
to the back, it probably went behind something else so now it is covered by
that something else.
Think of each object like a stack of cards that is in a specific order. When
the cards are stacked, only the top one shows. If you spread the cards out,
the order doesn't matter much except where they overlap. However, there is
still an order so if you move two cards to overlap, in the overlapping area,
only the front one will show. While you might be focusing on two cards
(objects), in reality all of the cards (objects) still have an order. For
example, you might have a line and a text box. The line might be object 1,
and the textbox might be object 36. The line is on top. If you choose Send
Backward, it will move the line to position 2 (still in front of position
36). You would actually have to move it back 36 times to get it behind the
text box.
Instead of moving it back 36 times, you might just choose Send to Back,
which puts in the back of everything. The problem with this is that object
52 might be a big piece of paper. All your lines and text boxes and other
things are on top of this paper unless you move one of them behind it. My
guess is that you have your big piece of paper (or something else that you
didn't notice) that was in the far back, but when you moved the line too far
back (possibly with Send to Back), you moved it behind the big piece of
paper.
--David
--
David M. Marcovitz
Author of _Powerful PowerPoint for Educators_
http://www.PowerfulPowerPoint.com/
Microsoft PowerPoint MVP
Associate Professor, Loyola University Maryland