Designation of the ARENA in which the mouse cursor can move

[Msha]

Is it possible to designate an arena, in which the mouse cursor, will randomly click, each time, during the exported action? I know that we can select "Random coordinates", and then in the offset we choose the value of pixels in which the mouse cursor can move. However, I want this value to be completely determined by me. To only edit the value of the length of the area. The width I do not need to change.