It appears that DraftSight is an AutoCAD clone and suffers from the problem of getting annotation properly sized in a scaled drawing sheet viewport. There is an option under Drafting Styles>Dimensions->Fit->Dimension scale that appears to address the issue by factoring in the viewsport scale.

How is this supposed to work? I cannot see any difference with the option being in effect as opposed to setting the DIMSCALE value to a fixed constant.