If the text comes from an overlay string via @code{before-string} or
@code{after-string} properties (@pxref{Overlay Properties}), or from a
display string (@pxref{Other Display Specs}), and the string doesn't
-contain a @code{face} or @code{mouse-face} property, but the buffer
-text affected by the overlay/display property does define a face,
-Emacs applies the face attributes of the ``underlying'' buffer text.
-Note that this is so even if the overlay or display string is
-displayed in the display margins (@pxref{Display Margins}).
+contain a @code{face} or @code{mouse-face} property, or these
+properties leave some face attributes undefined, but the buffer text
+affected by the overlay/display property does define a face or those
+attributes, Emacs applies the face attributes of the ``underlying''
+buffer text. Note that this is so even if the overlay or display
+string is displayed in the display margins (@pxref{Display Margins}).
@item
If any given attribute has not been specified during the preceding