How to add a slot to Active Assembly Editor List

I created a new slot. Can someone tell me how to add it to generic (basic) page Active Assembly list as shown on the image?

Wei,

After saving the Slot, did you refresh Content Explorer? You shouldn’t need to do more than that.

RLJII

I think you also have to add the new slot to at least one template of that content type.

This worked. Thank you for the suggestion.