While in Smart dimension, what does this cursor means?
When you dimension entities and a center line/construction line then you see this symbol.
R is for radius and D is for Diameter. Depending on your first dimension, the cursor would to R or D so that you don't have to select the center line/construction line again when dealing with other entities. It will stick to same behavior until you click ESC or select two entities.
Added video for better explanation. Check the D and R symbol next to cursor.
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