Confirmed here it has been removed with new release: Pickaxe Preview in the Editing Window - Bugs / Site Issues - Pickaxe Community Forum
I would like to see the return of the Preview button that opens a modal to review the pickaxe before finalizing any changes. I realize you can do this in the editor or go to direct link (after creating this deployment) but the button was something I used often to open the pickaxe within the admin spaces.