diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 09022883f71..263addd5a41 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -3535,13 +3535,14 @@ 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}).
+buffer text.  This does not apply to strings displayed in the display
+margins, which use the @code{margin} face as the base instead
+(@pxref{Display Margins}).
 
 @item
-If the text is to be shown in the display margins, and any given
-attribute has not been specified during the preceding steps, Emacs
-applies the attribute of the @code{margin} face.
+If the text is to be shown in the display margins, Emacs uses the
+@code{margin} face as the base, so any attribute not specified by the
+string's own face is taken from @code{margin}.
 
 @item
 If any given attribute has not been specified during the preceding
@@ -3825,7 +3826,9 @@ The basic face used for the text cursor.
 @item margin
 The basic face used for window margins, both on the left and on the
 right.  It is commonly used to customize the background of the empty
-areas of the margins.  It inherits from the @code{default} face.
+areas of the margins, and it also provides the base attributes for
+strings displayed in the margins (@pxref{Display Margins}).  It
+inherits from the @code{default} face.
 
 @item mouse
 The basic face used for displaying mouse-sensitive text when the mouse
@@ -5921,12 +5924,9 @@ the before-string.
 
   Note that if the string to be displayed in the margin doesn't fully
 specify its face, the nonspecified attributes are inherited from the
-@code{margin} face (@pxref{Basic Faces}).  The face merging mechanism
-ensures that the margin background remains consistent when margin
-annotations specify only a foreground color.  If you want a margin
-string to have a specific appearance independent of the @code{margin}
-face, make sure the string has a face specifying all required
-attributes.
+@code{margin} face (@pxref{Basic Faces}).  If you want a margin string
+to have a specific appearance independent of the @code{margin} face,
+make sure the string has a face specifying all required attributes.
 
   Before the display margins can display anything, you must give
 them a nonzero width.  The usual way to do that is to set these
diff --git a/etc/NEWS b/etc/NEWS
index 4c552389a8a..55b06a1cf93 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -95,6 +95,12 @@ left and right margin areas, which are used by various packages for
 per-line annotations.  Its background defaults to the frame default, so
 existing behavior is unchanged for users who do not customize it.
 
+Margin strings that do not fully specify their face now inherit the
+unspecified attributes from the 'margin' face.  If your code relied on
+the face of the underlying buffer text to specify the face attributes of
+strings displayed in the margin, you must now set their face on the margin
+string itself via 'propertize'.
+
 +++
 ** 'prettify-symbols-mode' attempts to ignore undisplayable characters.
 Previously, such characters would be rendered as, e.g., white boxes.