Good morning,
I am using the latest version of SolidWorks Community on latest and up to date version of Windows 11 Home on a i7 2.4GHz, 16 GB RAM, 64-bit processor. 
I am new to SolidWorks, although used CAD systems extensively 30 years ago.
What an improvement in capabilities.
I am trying to add a dimension to my saw horse plan highlighting the width of a leg for the saw horse (45mm).
The Smart Dimension keeps dimensioning the vertical distance, not the parallel distance (see attached picture).

Any guidance will be most appreciated.
 

Thanking you
Peter