Thing that drives me crazy about tables

Word 2003.
I'm doing long and complex documents with all the information organized in
tables.

I've noticed that my tables randomly become flat so that I can't size them
with my cursor. Sometimes I can size width only - I never need to size width,
so this doesn't help me. Other times I can't size the file in any direction.

Print Preview doesn't work, and neither does Table Properties.

The first time I noticed this was when I split a column into three or four
cells. It was to the left of a column that was NOT split. I could no longer
lower or raise the cell height. Typically a split column is fine, but that
was the first place I noticed it. Then it occurred more and more often
throughout the document, affecting regular non-split cells as well.

I have to create new cells ALL THE TIME and cut/paste the content into them,
then delete the flat cells. I've tried copy/pasting the entire document into
a new document in case it had gotten corrupt - no good. It's really annoying.
Does anyone have any suggestions on how to avoid this?