How to open the dialog box dynamically in iOS?

How do I shrink a dialog box?

• I have a personal laptop. The program is Windows 7. I use the free program, Paint to make and edit pictures. In Paint when I click on the "paste from" button, the dialog box of my pictures files pop up so I can pick what picture to paste. The dialog box doesn't have the minimize or maximize buttons. But by putting the cursor on the border of the dialog box makes it an arrow to shrink or enlarge the dialog box. But recently, somehow on it's own, the dialog box enlarged to full screen and got stuck. I can't shrink it back with the cursor arrow. How do I shrink the dialog box so it doesn't cover the full screen and can change the size whenever?

• Answer:

  click the icon on the top left of the title bar of the window then click size