diff --git a/dom/locales/en-US/chrome/dom/dom.properties b/dom/locales/en-US/chrome/dom/dom.properties
index 96fabb4a2495..4679a2acc2e2 100644
--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -124,7 +124,7 @@ PluginHangUIMessage=%S may be busy, or it may have stopped responding. You can s
 PluginHangUIWaitButton=Continue
 PluginHangUIStopButton=Stop plugin
 # LOCALIZATION NOTE: Do not translate "mozHidden", "mozVisibilityState", "hidden", or "visibilityState"
-PrefixedVisibilityApiWarning='mozHidden' and 'mozVisibilityState' are deprecated.  Please use the unprefixed 'hidden' and 'visibilityState' instead.
+PrefixedVisibilityAPIWarning='mozHidden' and 'mozVisibilityState' are deprecated.  Please use the unprefixed 'hidden' and 'visibilityState' instead.
 # LOCALIZATION NOTE: Do not translate "NodeIterator" or "detach()".
 NodeIteratorDetachWarning=Calling detach() on a NodeIterator no longer has an effect.
 # LOCALIZATION NOTE: Do not translate "LenientThis" and "this"
diff --git a/webapprt/locales/en-US/webapprt/overrides/dom.properties b/webapprt/locales/en-US/webapprt/overrides/dom.properties
index 11c8e065049f..9aa90e8333c5 100644
--- a/webapprt/locales/en-US/webapprt/overrides/dom.properties
+++ b/webapprt/locales/en-US/webapprt/overrides/dom.properties
@@ -120,7 +120,7 @@ PluginHangUIMessage=%S may be busy, or it may have stopped responding. You can s
 PluginHangUIWaitButton=Continue
 PluginHangUIStopButton=Stop plugin
 # LOCALIZATION NOTE: Do not translate "mozHidden", "mozVisibilityState", "hidden", or "visibilityState"
-PrefixedVisibilityApiWarning='mozHidden' and 'mozVisibilityState' are deprecated. Please use the unprefixed 'hidden' and 'visibilityState' instead.
+PrefixedVisibilityAPIWarning='mozHidden' and 'mozVisibilityState' are deprecated. Please use the unprefixed 'hidden' and 'visibilityState' instead.
 # LOCALIZATION NOTE: Do not translate "NodeIterator" or "detach()".
 NodeIteratorDetachWarning=Calling detach() on a NodeIterator no longer has an effect.
 # LOCALIZATION NOTE: Do not translate "LenientThis" and "this"