Photoshop CC 2015.5 introduced the new Select and Mask Workspace and removed the old Refine Edge (Refine Mask) dialog box. If you prefer to use the old dialog box when working with selections, then use this little-known shortcut in Photoshop CC 2017 and newer to bring back the Refine Edge dialog box.
With a selection or mask active, press-and-hold Shift, and go to Select > Select and Mask. This will open the Refine Edge window instead of the Select and Mask Workspace!
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