diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -956,6 +956,9 @@
 coreconfigitem('stack', 'restrict-ancestors',
     default=True,
 )
+coreconfigitem('experimental', 'stack.same-branch',
+    default=False,
+)
 coreconfigitem('subrepos', 'allowed',
     default=dynamicdefault,  # to make backporting simpler
 )
diff --git a/mercurial/stack.py b/mercurial/stack.py
--- a/mercurial/stack.py
+++ b/mercurial/stack.py
@@ -41,6 +41,10 @@
         revspecargs.append("not ::merge()")
         revspec.append("%r")
 
+    if repo.ui.configbool("experimental", "stack.same-branch"):
+        revspecargs.append(revsetlang.formatspec("branch(%s)", rev))
+        revspec.append("%r")
+
     finalrevspec = " and ".join(revspec)
     revset = revsetlang.formatspec(finalrevspec, *revspecargs)
     revisions = scmutil.revrange(repo, [revset])
diff --git a/tests/test-stack.t b/tests/test-stack.t
--- a/tests/test-stack.t
+++ b/tests/test-stack.t
@@ -51,6 +51,25 @@
   o  0 other draft c_a
   
 
+Check that stack show draft changesets from all branches by default
+-------------------------------------------------------------------
+
+  $ hg debugstack
+  0
+  1
+  2
+  3
+  4
+  5
+
+But not if we restrict on the branch
+
+  $ hg debugstack --config experimental.stack.same-branch=true
+  2
+  3
+  4
+  5
+
 Check that stack doesn't include public changesets
 --------------------------------------------------