Invest a little time to learn what's going on with the Layout tab on the
Format > TextBox dialog, including the options on the Advanced tab. The
position is affected by the form of positioning (in-line, square, tight, top
and bottom, etc), and by whether 'Allow overlap' is checked.
I've had issues where the Absolute Postion field on the Advanced Layout |
Picture Postion field gets set to some ridiculous value like -9.89. Even when
I correct it, some movements of the graphics will cause Word to 'forget' that
value and put a 'garbage' value in the field, which cause the textbox to jump
to the top of the page.
Also if the TextBox gets too close to the top/bottom margin, Word seems to
try and reposition it, many times in ways that are unexpected.
This can happen if Vertical Alignment is set to "Center" in Page
Setup. It is a bug. The easy work-around is either don't do centered
vertical alignment, or if you do, don't drag things.