The dimension can not be modified

In drawing sheet, I created several dimensions with smart dimension, I can not change those dimensions, because they are grey when I click it, but when I created those dimension with inserting model items, the dimension can be modified , I have no idea why. Does anyone has the same problem as me ? Is it possible to solve the issue? I do not want to use inserting model items to create dimensions, because of a lot of un-wanted dimensions.

Any tips will be appreciated.

Thanks in advance

Andrew

SolidworksDrawings And Detailing