Subject: 27.1; Display problem with minibuffer overlay when using display property

From: Clemens <[email-masked]>
Date: Fri, 29 Jan 2021 18:58:46 +0100

When using an overlay with an `after-string` which uses `display`
the prompt background bleeds into the after string:

(set-face-attribute 'minibuffer-prompt nil :background "purple")

(minibuffer-with-setup-hook
     (lambda ()
       (overlay-put
        (make-overlay (point-max) (point-max) nil t t)
        'after-string (propertize " world"
                                  'display
				 " minibuffer")))
   (read-string "Hello"))

While I would expect it to be displayed like when using:

(minibuffer-with-setup-hook
     (lambda ()
       (overlay-put
        (make-overlay (point-max) (point-max) nil t t)
        'after-string " minibuffer"))
   (read-string "Hello"))