SYMPTOM:
Users have the ability to check the box 'Allow height to shrink' for the Document Header section in Strategy Web 9.x. However, there will still be empty space displayed between the Document Header and Detail Header sections when exported to HTML. Refer to the two images below for comparison.
Exported to PDF.

Exported to HTML.

STEPS TO REPRODUCE:
CAUSE:
This is a known issue in Strategy Web 9.x.
ACTION:
Contact Strategy Technical Support for an update on this issue.