* wid-edit.el (widget-button-click): For mouse-1, cancel button

	press and perform default action if we get a mouse movement event.

2 files changed, 70 insertions, 53 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 670f6db6282..5dc2fec8b97 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2006-02-16  Chong Yidong  <cyd@stupidchicken.com>
+
+	* wid-edit.el (widget-button-click): For mouse-1, cancel button
+	press and perform default action if we get a mouse movement event.
+
 2006-02-16  Juanma Barranquero  <lekktu@gmail.com>
 
 	* calendar/icalendar.el (icalendar--get-event-property)
diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index 659c562ea65..fc64dd5f361 100644
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -916,67 +916,79 @@ Recommended as a parent keymap for modes using widgets.")
   "Invoke the button that the mouse is pointing at."
   (interactive "e")
   (if (widget-event-point event)
-      (let* ((pos (widget-event-point event))
+      (let* ((oevent event)
+	     (mouse-1 (memq (event-basic-type event) '(mouse-1 down-mouse-1)))
+	     (pos (widget-event-point event))
 	     (start (event-start event))
 	     (button (get-char-property
 		      pos 'button (and (windowp (posn-window start))
 				       (window-buffer (posn-window start))))))
-	(if button
-	    ;; Mouse click on a widget button.  Do the following
-	    ;; in a save-excursion so that the click on the button
-	    ;; doesn't change point.
-	    (save-selected-window
-	      (select-window (posn-window (event-start event)))
-	      (save-excursion
-		(goto-char (posn-point (event-start event)))
-		(let* ((overlay (widget-get button :button-overlay))
-		       (pressed-face (or (widget-get button :pressed-face)
-					 widget-button-pressed-face))
-		       (face (overlay-get overlay 'face))
-		       (mouse-face (overlay-get overlay 'mouse-face)))
-		  (unwind-protect
-		      ;; Read events, including mouse-movement events
-		      ;; until we receive a release event.  Highlight/
-		      ;; unhighlight the button the mouse was initially
-		      ;; on when we move over it.
-		      (save-excursion
-			(when face	; avoid changing around image
-			  (overlay-put overlay 'face pressed-face)
-			  (overlay-put overlay 'mouse-face pressed-face))
-			(unless (widget-apply button :mouse-down-action event)
-			  (let ((track-mouse t))
-			    (while (not (widget-button-release-event-p event))
-			      (setq event (read-event)
-				    pos (widget-event-point event))
-			      (if (and pos
-				       (eq (get-char-property pos 'button)
-					   button))
-				  (when face
-				    (overlay-put overlay 'face pressed-face)
-				    (overlay-put overlay 'mouse-face pressed-face))
-				(overlay-put overlay 'face face)
-				(overlay-put overlay 'mouse-face mouse-face)))))
-
-			;; When mouse is released over the button, run
-			;; its action function.
-			(when (and pos
-				   (eq (get-char-property pos 'button) button))
-			  (widget-apply-action button event)))
-		    (overlay-put overlay 'face face)
-		    (overlay-put overlay 'mouse-face mouse-face))))
-
-	      (unless (pos-visible-in-window-p (widget-event-point event))
-		(mouse-set-point event)
-		(beginning-of-line)
-		(recenter))
-	      )
-
+	(when (or (null button)
+		  (catch 'button-press-cancelled
+	      ;; Mouse click on a widget button.  Do the following
+	      ;; in a save-excursion so that the click on the button
+	      ;; doesn't change point.
+	      (save-selected-window
+		(select-window (posn-window (event-start event)))
+		(save-excursion
+		  (goto-char (posn-point (event-start event)))
+		  (let* ((overlay (widget-get button :button-overlay))
+			 (pressed-face (or (widget-get button :pressed-face)
+					   widget-button-pressed-face))
+			 (face (overlay-get overlay 'face))
+			 (mouse-face (overlay-get overlay 'mouse-face)))
+		    (unwind-protect
+			;; Read events, including mouse-movement
+			;; events, waiting for a release event.  If we
+			;; began with a mouse-1 event and receive a
+			;; movement event, that means the user wants
+			;; to perform drag-selection, so cancel the
+			;; button press and do the default mouse-1
+			;; action.  For mouse-2, just highlight/
+			;; unhighlight the button the mouse was
+			;; initially on when we move over it.
+			(save-excursion
+			  (when face	; avoid changing around image
+			    (overlay-put overlay 'face pressed-face)
+			    (overlay-put overlay 'mouse-face pressed-face))
+			  (unless (widget-apply button :mouse-down-action event)
+			    (let ((track-mouse t))
+			      (while (not (widget-button-release-event-p event))
+				(setq event (read-event))
+				(when (and mouse-1 (mouse-movement-p event))
+				  (push event unread-command-events)
+				  (setq event oevent)
+				  (throw 'button-press-cancelled t))
+				(setq pos (widget-event-point event))
+				(if (and pos
+					 (eq (get-char-property pos 'button)
+					     button))
+				    (when face
+				      (overlay-put overlay 'face pressed-face)
+				      (overlay-put overlay 'mouse-face pressed-face))
+				  (overlay-put overlay 'face face)
+				  (overlay-put overlay 'mouse-face mouse-face)))))
+
+			  ;; When mouse is released over the button, run
+			  ;; its action function.
+			  (when (and pos
+				     (eq (get-char-property pos 'button) button))
+			    (widget-apply-action button event)))
+		      (overlay-put overlay 'face face)
+		      (overlay-put overlay 'mouse-face mouse-face))))
+
+		;; This loses if the widget action switches windows. -- cyd
+		;; (unless (pos-visible-in-window-p (widget-event-point event))
+		;;   (mouse-set-point event)
+		;;   (beginning-of-line)
+		;;   (recenter))
+		)
+	      nil))
 	  (let ((up t) command)
 	    ;; Mouse click not on a widget button.  Find the global
 	    ;; command to run, and check whether it is bound to an
 	    ;; up event.
-	    (mouse-set-point event)
-	    (if (memq (event-basic-type event) '(mouse-1 down-mouse-1))
+	    (if mouse-1
 		(cond ((setq command	;down event
 			     (lookup-key widget-global-map [down-mouse-1]))
 		       (setq up nil))