Set it to slide and "also resize enclosing part". Then select the same settings for all the fields and other layout objects below it so that they will slide up as well.
The results will be visible in preview mode and when you print/PDF the report, but not in browse mode.
I had neglected to set a couple of items BELOW the top text field to slide up and shrink. Fixing them allowed the top field to shirnk. Seems strange but it worked. Thanks. Howard
They don't shrink, of course, but they do "slide up". FileMaker uses the same poperty setting in the inspector for both--odd, but it's always been set up in that funky manner all the way back to FileMaker 2.5 at least. (First version I ever used.)