In one of my InDesign (16.0.2) files the Smart Guides do not show up, although they are all checked in the Preferences. In that problem file, in the Menu option >View >Grids and Guides > Smart Guides, the option Smart Guides is checked, but appears in grey (see attached pdf). When I open a different InDesign file, everything is OK. Does anybody know what could possibly cause this problem? Please let me know!