BUMMER-- Just found this…

NoteCustom buttons that point to a URL or call JavaScript aren’t supported in Lightning Experience.

Yep – sad but true.

So is there no way to use clean anymore? 

Any changes to this since I posted the last time? We have “skuid view” buttons on many of our pages and prefer these over page overrides as our skuid pages pull in many custom objects that work together. If we cannot use buttons, is there a way to go from a lightning page to a skuid view of that page without a button while using a lightning enabled org?

Can you point the button to a tab or a visualforce page, or is that considered a URL? Don’t know much about lightning, obviously…

You can point it to a visualforce page. I just do not see how to add buttons in lightning.