Problem with Meetings Module

I customized the meetings module form, and somehow the bottom of the page with “Scheduling” where you can invite multiple people through clicking “Add Invitees” is completely missing.

I checked against other form configurations on another CRM installation, and looked at the previous revisions of the form - there’s no item to add through the form editor that would cause this to show (or not show, if removed) that I can find.

Any ideas why this has vanished?

I fixed this, by accident. I had added the duration_dom dropdown to my form, which somehow made the duration not sync to the end date. I removed the explicit duration_dom dropdown, and used the default Duration field in the form; which fixed syncing the End Date, and I belive re-added the “Scheduling” pane.