Title Header not 'Resizing'

[Wickerman]

I'm going nuts here -- I've got a really simple Title header for a report.  All that's in there is a single Text box with two merge fields in it. I have it set to 'Sliding Up based on all objects above, and have checked the box that says "Also resize enclosing part."  I've made sure nothing is overlapping the division between the Title Header and body parts.  But in preview the text box is closing up properly but the 'Enclosing Part' isn't resizing to take up the excess empty space created by the Text box.  Attached are pictures of the layout, the Preview and my little control box.  I've put a border around the text box and given the Title Header a yellow fill.  

What the heck can I be overlooking here?  Sliding / Re-sizing is working fine on the body Part.

[comment]

Quote

Headers, footers, title headers, title footers, and top navigation and bottom navigation parts never shrink or slide up.

http://www.filemaker.com/help/15/fmp/en/#page/FMP_Help%2Fremoving-blank-spaces.html

[Wickerman]

Ah . . . "You can set layout parts to shrink when the fields in them slide up. Headers, footers, title headers, title footers, and top navigation and bottom navigation parts never shrink or slide up."

I could have sworn I had a sliding header working before.  Oh well -- thanks for the reference.