I know lightning doesn't support javascript buttons. I know there are alternative routes to do this with actions, lightning components, and visualforce. I'm asking how to do something that according to my research is supported but doesn't seem to work.
From the spring '16 release notes
Custom buttons and links that define their content source as URL are now supported in Lightning Experience and the Salesforce1 mobile app. This feature was previously available in Salesforce Classic only.
Seems straight forward. Create the button, add it to the classic page layout, see it in lightning. But for the life of me, I can't figure out how to get this thing to show up.
Here's the custom button, pretty basic
I've got it setup as the only button on the page layout, it's the assigned layout when I edit the page in lightning.
But in lightning I'm getting nothing
What am I doing wrong? Seems like I'm following the instructions outlined in this trailhead. Even though it's in the release notes, it's not mentioned in the help docs on actions in lightning. Other peopler have had issues and have gotten it working eventually. What am I missing? Are there other factors to consider? Are those documented anywhere?