diff --git a/mercurial/crecord.py b/mercurial/crecord.py
--- a/mercurial/crecord.py
+++ b/mercurial/crecord.py
@@ -990,6 +990,16 @@ class curseschunkselector(object):
                     self.toggleapply(item)
         self.waslasttoggleallapplied = not self.waslasttoggleallapplied
 
+    def flipselections(self):
+        """
+        Flip all selections. Every selected line is unselected and vice
+        versa.
+        """
+        for header in self.headerlist:
+            for hunk in header.allchildren():
+                for line in hunk.allchildren():
+                    self.toggleapply(line)
+
     def toggleallbetween(self):
         """toggle applied on or off for all items in range [lastapplied,
         current]. """
@@ -1638,7 +1648,7 @@ smaller changesets. the following are va
                  ctrl-l : scroll the selected line to the top of the screen
                       m : edit / resume editing the commit message
                       e : edit the currently selected hunk
-                      a : toggle amend mode, only with commit -i
+                      a : toggle all selections
                       c : confirm selected changes
                       r : review/edit and confirm selected changes
                       q : quit without confirming (no changes will be made)
@@ -1914,7 +1924,7 @@ are you sure you want to review/edit and
         elif keypressed in ["q"]:
             raise error.Abort(_(b'user quit'))
         elif keypressed in ['a']:
-            self.toggleamend(self.opts, test)
+            self.flipselections()
         elif keypressed in ["c"]:
             return True
         elif keypressed in ["r"]:
diff --git a/tests/test-commit-interactive-curses.t b/tests/test-commit-interactive-curses.t
--- a/tests/test-commit-interactive-curses.t
+++ b/tests/test-commit-interactive-curses.t
@@ -95,7 +95,7 @@ Committing only one hunk while aborting 
 - unfold it
 - go down to second hunk (1 for the first hunk, 1 for the first hunkline, 1 for the second hunk, 1 for the second hunklike)
 - toggle the second hunk
-- toggle on and off the amend mode (to check that it toggles off)
+- toggle all lines twice (to check that it does nothing)
 - edit the hunk and quit the editor immediately with non-zero status
 - commit
 
@@ -193,20 +193,39 @@ Newly added files can be selected with t
   $ hg st
   ? testModeCommands
 
-Amend option works
+Test toggling all selections works
+
+- Change one line
+- Add an extra line at the end
+- Unselect all
+- Select the extra line at the end
+- Toggle all selections (so the extra line at the is unselected and the modified line is selected)
+- Commit
+
   $ echo "hello world" > x
-  $ hg diff -c .
-  diff -r a6735021574d -r 2b0e9be4d336 x
-  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+  $ echo "goodbye world" >> x
+  $ hg diff
+  diff -r 2b0e9be4d336 x
+  --- a/x	Thu Jan 01 00:00:00 1970 +0000
   +++ b/x	Thu Jan 01 00:00:00 1970 +0000
-  @@ -0,0 +1,1 @@
-  +hello
+  @@ -1,1 +1,2 @@
+  -hello
+  +hello world
+  +goodbye world
   $ cat <<EOF >testModeCommands
+  > f
+  > j
+  > x
+  > j
+  > j
+  > j
+  > x
   > a
   > c
   > EOF
-  $ hg commit -i  -m "newly added file" -d "0 0"
+  $ hg commit -i --amend  -m "newly added file" -d "0 0" x
   saved backup bundle to $TESTTMP/a/.hg/strip-backup/2b0e9be4d336-3cf0bc8c-amend.hg
+  $ hg rev x --no-backup
   $ hg diff -c .
   diff -r a6735021574d -r c1d239d165ae x
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000