To change the scale, enter a factor into the Zoom Factor entry area, and press the associated Apply button. Factors greater that 1.0 will zoom out.
Alternatively, one can enter the center x and y values and width (all in microns) of a new region to display. The coordinates are relative to the origin of the displayed cell. The width is the displayed width of the region to be displayed in the window, the displayed height will depend on the drawing window's aspect ratio. Pressing the associated Apply button will redisplay the new location.
The windowing parameter entries are pre-loaded with the current window parameters, and track any changes made when the pop-up is visible.
The right mouse button (button 3) can also be used to zoom, as can the numeric keypad + and - keys which zoom in and out by a factor of two, or by ten percent if Shift is also held.