Open your form in Design Mode.
Press Alt-F4 to get the propeties window if it is';t already open and click the All tab - set Default View to Single Form and Auto resize to No.
Click the Detail Section near your buttons. Now that you have the Detail Section selected resize it to the size you want - not the form window but the part that moves next to the horizontal and vertical rulers.
Save your form and close.
Reopen and it should be the size you want.
