--- a/layout/base/AccessibleCaretManager.cpp
+++ b/layout/base/AccessibleCaretManager.cpp
@@ -191,19 +191,20 @@ AccessibleCaretManager::OnSelectionChang
 
   // For mouse input we don't want to show the carets.
   if (sHideCaretsForMouseInput &&
       mLastInputSource == nsIDOMMouseEvent::MOZ_SOURCE_MOUSE) {
     HideCarets();
     return NS_OK;
   }
 
-  // No need to show the carets for select all action when we want to hide
-  // the carets for mouse input.
+  // When we want to hide the carets for mouse input, hide them for select
+  // all action fired by keyboard as well.
   if (sHideCaretsForMouseInput &&
+      mLastInputSource == nsIDOMMouseEvent::MOZ_SOURCE_KEYBOARD &&
       (aReason & nsISelectionListener::SELECTALL_REASON)) {
     HideCarets();
     return NS_OK;
   }
 
   UpdateCarets();
   return NS_OK;
 }