The window that this OPEN WINDOW statement describes cannot be opened because its border does not fit on the screen. Despite the wording of the message, the window is not necessarily too large for the screen. However, one or more of its borders (top, bottom, left, or right) cannot be drawn. The position of the window is set in the OPEN WINDOWS statement; check that it starts no higher than row 2 and no farther left than column 2 (or else remove the BORDER attribute). The OPEN WINDOW statement or the form that it names sets the size of the window.
The dimensions of the terminal for UNIX systems are determined when the program starts by reading termcap information (or terminfo information, depending on the value of the INFORMIXTERM environment variable). If the termcap entry includes sg#1 (terminfo: xmc#1), 4GL reserves an additional column to the left and right of a bordered window. On DOS systems, the window size is always 24 lines by 80 characters.