Zoom In
Click the button [Zoom In].
By this, the Graph window will be in "Zoom In mode".
In this mode, the area selected as a rectangle by dragging on the Graph area will be expanded to the full Graph window.
If you just double-click on the Graph area, it will be expanded to double scale around the clicked point.
To cancel Zoom in during dragging, click right button and then click the left button at the same time.