Clicking Smart Dimension button with sketch geometry selected

I moved from SolidWorks 2014 to SolidWorks 2017 this year, and I feel like there's been a change in how dimensions are added to sketches.

I'm pretty sure that in the past, when editing a sketch, if I had some geometry selected - e.g. a line - and I then clicked the Smart Dimension button, the sketch geometry would become deselected and I would be able to then add the Smart Dimension to any geometry I wanted.

Now if I click the Smart Dimension button with the line selected a length dimension will automatically be created on the selected line.

Is this a new feature? If so, is there any way I can turn it off?

Thanks,

Chris