Improve DND documentation

* doc/lispref/frames.texi (Drag and Drop):
* src/xfns.c (Fx_begin_drag): Document meaning of
`XdndActionPrivate'.

diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index 31ebeb51b41bc4e1fc00d88937b05cd17f658181..9717fa2978647d7d9fba591815f36e13fd0fd5ae 100644 (file)
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -4070,7 +4070,10 @@ while also being able to drag content to other programs.
 If the drop was rejected or no drop target was found, this function
 returns @code{nil}.  Otherwise, it returns a symbol describing the
 action the target chose to perform, which can differ from @var{action}
-if that isn't supported by the drop target.
+if that isn't supported by the drop target.  @code{XdndActionPrivate}
+is also a valid return value in addition to @code{XdndActionCopy} and
+@code{XdndActionMove}, and means that the drop target chose to perform
+an unspecified action.
 @end defun
 
 @node Color Names

diff --git a/src/xfns.c b/src/xfns.c
index 9d30f2adee14aae4ec36af23964dff0e4924f322..eae409eed240e046225131c4856070686de0cf88 100644 (file)
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -6601,6 +6601,9 @@ can be one of the following:
    `XdndSelection', and to delete whatever was saved into that
    selection afterwards.
 
+`XdndActionPrivate' is also a valid return value, and means that the
+drop target chose to perform an unspecified or unknown action.
+
 There are also some other valid values of ACTION that depend on
 details of both the drop target's implementation details and that of
 Emacs.  For that reason, they are not mentioned here.  Consult