Blank space at end of page

Background

A subreport with a column title and a detail section both set to 20px high.

When the subreport record displays on the main report, the subreport prints as expected until when it reaches at the bottom of the page.

Then the subreport prints just the column header and left blank space, then again starts on new page with column header and its detail.

Question

So, would you make it either print the whole subreport on same page, or start whole report from new page?

Master Report JRXML

http://pastebin.com/V2HRPWVL

Image of the problem faces

Thank You
Mihir Parekh