Making a square selection

[cday]

Is there a way to constrain a dragged selection to be an exact square?

If not in XnView Classic, in XnViewMP?

[xnview]

by using ratio 1:1 or in XnViewMP by pressing shift

[cday]

by using ratio 1:1 or in XnViewMP by pressing shift

Thanks, for reference:

XnView Classic required setting: Edit > Set Selection ratio -- 1:1

XnViewMP required setting: Tools > Settings... > Interface > Mouse -- Left button -- Make selection