=== modified file 'lisp/window.el'
--- lisp/window.el	2012-09-16 04:52:38 +0000
+++ lisp/window.el	2012-09-16 17:38:02 +0000
@@ -2394,27 +2394,32 @@
 This function is only called by the minibuffer window resizing
 routines.  It resizes windows proportionally and never deletes
 any windows."
-  (when (numberp delta)
-    (let (ignore)
-      (cond
-       ((< delta 0)
-	(setq delta (window-sizable window delta)))
-       ((> delta 0)
-	(unless (window-sizable window delta)
-	  (setq ignore t))))
-
-      (window--resize-reset (window-frame window))
-      ;; Ideally, we would resize just the last window in a combination
-      ;; but that's not feasible for the following reason: If we grow
-      ;; the minibuffer window and the last window cannot be shrunk any
-      ;; more, we shrink another window instead.  But if we then shrink
-      ;; the minibuffer window again, the last window might get enlarged
-      ;; and the state after shrinking is not the state before growing.
-      ;; So, in practice, we'd need a history variable to record how to
-      ;; proceed.  But I'm not sure how such a variable could work with
-      ;; repeated minibuffer window growing steps.
-      (window--resize-this-window window delta nil ignore t)
-      delta)))
+  (let (ignore)
+    (cond
+     ((not (numberp delta))
+      (setq delta 0))
+     ((zerop delta))
+     ((< delta 0)
+      (setq delta (window-sizable window delta))
+      (window--resize-reset (window-frame window))
+      ;; When shrinking the root window, emulate an edge drag in order
+      ;; to not resize other windows if we can avoid it (Bug#12419).
+      (window--resize-this-window
+       window delta nil ignore t 'before
+       (+ (window-top-line window) (window-total-size window)))
+      ;; Don't record new normal sizes to make sure that shrinking back
+      ;; proportionally works as intended.
+      (walk-window-tree
+       (lambda (window) (set-window-new-normal window 'ignore))))
+     ((> delta 0)
+      (window--resize-reset (window-frame window))
+      (unless (window-sizable window delta)
+	(setq ignore t))
+      ;; When growing the root window, resize proportionally.  This
+      ;; should give windows back their original sizes (hopefully).
+      (window--resize-this-window window delta nil ignore t)))
+     ;; Return the possibly adjusted DELTA.
+     delta))
 
 (defun adjust-window-trailing-edge (window delta &optional horizontal)
   "Move WINDOW's bottom edge by DELTA lines.