The Zoom command creates a special, not sizable, Zoom window with three panes and resizes and stacks the Baseline, Differences, and Result windows.
All three zoomed portions show the same part of the bitmap. When you move the mouse within any of the three windows, the bitmap tool generates a simultaneous and synchronized real-time display in all three panes of the Zoom window.
While in scan mode, you can capture the Zoom window to examine a specific bitmap difference.