Hello,
I've found that the RadzenNumeric ShowUpDown property is inverted in VS.
The RadzenNumeric component is inside a RadzenSteps component (not sure if this is important or not).
In the first image I've highlighted the ShowUpDown property within RBS along with the markup code. Here you can see the property is ON (set).
In the next image I've highlighted the ShowUpDown property in VS along with the markup code. Here you can see the property is OFF (clear).
Both VS and RBS are running with the same solution open. RBS for VS is 1.5.1 and RBS is 1.36.3.