FixedSize resource

Specifies a fixed size for the x3270 display window. If set, x3270 will not allow its window to be resized by the window manager. The 3270 display screen will float in the center of the window if necessary.

The syntax is widthxheight.

Examples
Float the x3270 display in a window that is 1000 pixels wide and 800 pixels high. 1000x800