From what I can see, opening the designer and closing it will change nothing. If I click on a label, just the action of touching it causes a recalculation of the height and width for that label only.

Anyway what I just did for the height was build a table of all the fonts and fontsizes I use [there are only about 8 combinations], and stick those into the height field. Previously I put in an approximate value based only on the fontsize. So the height should now be correct.

It's possible it only uses the height when calculating band sizes and overflows and page breaks, none of which apply to this form. In which case a wrong height will not interfere with the printing of the string.