This view window is set to the 'normal' view:
When the hex column is resized by dragging the divider in the header, the row length of the view changes, and thus the width of the 'characters' column changes.
The grey divider between the two columns doesn't do anything; the view just looks ugly without it.
Throughout AXE, the way hex values are translated to characters can depend on your system's settings,
and on whether you are running NT or 95. AXE simply uses whatever code page is your default.