It appears the window has been "resized" down to its minimum dimensions. Since SchoolLeader always remembers the last size and position of a window, it will continue to display this way until you resize it back to the proper size.
To resize a window, simply move the cursor to any of the four corners of the box. The mouse cursor will change to a double-headed arrow. Once that happens click and hold the Index finger button down while you "drag" the edge outward from the center. This will resize the box. When it has reached the desired size simply let go of the button and the window will remain at that size from that point on.