Fode, please read the manual section on the Video Display and how it is sized and positioned. Click the Help menu, Read Manual command to do this. The Video Display link is found in the right column of the Table of Contents.
Once you understand how it works, I think your problem will be solved.
Do pay attention to the post above on "Clone mode". This is a setting for your dual display graphics card that you may need to make. Read the directions on this
Hoster Faq page.