Columns not responsive

I no longer see a way to make s column set to 4 in a row responsive. The column html code ends up col-4 and it used to be able to choose md to set width to 4. I searched for a way to do it like I previously did a few weeks ago but I do not see it. It should be col-md-4 or have a choice of cos etc... is it a bug? Or am I missing something? Any help is appreciated. Thanks

Never mind. I found where to drill down... Duh. Blond girl strikes again! No bug here. Sorry

LOL I came here for the same question. not blond guy. Saw your post and thought what am I missing?

For others that follow in this quest for enlightenment. Click the > icon next to the width selector in column property panel to get the break points showing...

Thank you Sarah.