Position that textboxes are rendered in Internet Explorer

I have a report with a number of textboxes (image attached) in a 3 by 3 grid. They are all 5 pixels apart as indicated by BIDS at design time:

When I render it in Internet Explorer, right right hand column of textboxes are shifted to the right hand side of the window:

I would like it to appear as the report in design time. How is this controlled and how do I affect it? Some sort of glueing to the RHS would be useful sometimes, like the Anchor property in Windows Forms, but it needs to be under the control of the developer.

Any advice for resolving this gratefully received. Thanks,

Mark

Mark Roworth