diff --git a/dom/base/nsCopySupport.cpp b/dom/base/nsCopySupport.cpp
index 0db373936b9c..fa8e28c9cf93 100644
--- a/dom/base/nsCopySupport.cpp
+++ b/dom/base/nsCopySupport.cpp
@@ -755,8 +755,13 @@ nsCopySupport::FireClipboardEvent(EventMessage aEventMessage,
     *aActionTaken = false;
   }
 
-  NS_ASSERTION(aEventMessage == eCut || aEventMessage == eCopy ||
-               aEventMessage == ePaste,
+  EventMessage originalEventMessage = aEventMessage;
+  if (originalEventMessage == ePasteNoFormatting) {
+    originalEventMessage = ePaste;
+  }
+
+  NS_ASSERTION(originalEventMessage == eCut || originalEventMessage == eCopy ||
+               originalEventMessage == ePaste,
                "Invalid clipboard event type");
 
   nsCOMPtr<nsIPresShell> presShell = aPresShell;
@@ -813,10 +818,10 @@ nsCopySupport::FireClipboardEvent(EventMessage aEventMessage,
   if (chromeShell || Preferences::GetBool("dom.event.clipboardevents.enabled", true)) {
     clipboardData =
       new DataTransfer(doc->GetScopeObject(), aEventMessage,
-                       aEventMessage == ePaste, aClipboardType);
+                       originalEventMessage == ePaste, aClipboardType);
 
     nsEventStatus status = nsEventStatus_eIgnore;
-    InternalClipboardEvent evt(true, aEventMessage);
+    InternalClipboardEvent evt(true, originalEventMessage);
     evt.mClipboardData = clipboardData;
     EventDispatcher::Dispatch(content, presShell->GetPresContext(), &evt,
                               nullptr, &status);
@@ -827,7 +832,7 @@ nsCopySupport::FireClipboardEvent(EventMessage aEventMessage,
   // No need to do anything special during a paste. Either an event listener
   // took care of it and cancelled the event, or the caller will handle it.
   // Return true to indicate that the event wasn't cancelled.
-  if (aEventMessage == ePaste) {
+  if (originalEventMessage == ePaste) {
     // Clear and mark the clipboardData as readonly. This prevents someone
     // from reading the clipboard contents after the paste event has fired.
     if (clipboardData) {
@@ -867,7 +872,7 @@ nsCopySupport::FireClipboardEvent(EventMessage aEventMessage,
 
     // when cutting non-editable content, do nothing
     // XXX this is probably the wrong editable flag to check
-    if (aEventMessage != eCut || content->IsEditable()) {
+    if (originalEventMessage != eCut || content->IsEditable()) {
       // get the data from the selection if any
       bool isCollapsed;
       sel->GetIsCollapsed(&isCollapsed);
diff --git a/dom/events/DataTransfer.cpp b/dom/events/DataTransfer.cpp
index 26d2320d624d..5d31d2cb300b 100644
--- a/dom/events/DataTransfer.cpp
+++ b/dom/events/DataTransfer.cpp
@@ -105,8 +105,11 @@ DataTransfer::DataTransfer(nsISupports* aParent, EventMessage aEventMessage,
       aEventMessage == eDragStart) {
     mReadOnly = false;
   } else if (mIsExternal) {
-    if (aEventMessage == ePaste) {
-      CacheExternalClipboardFormats();
+    if (aEventMessage == ePasteNoFormatting) {
+      mEventMessage = ePaste;
+      CacheExternalClipboardFormats(true);
+    } else if (aEventMessage == ePaste) {
+      CacheExternalClipboardFormats(false);
     } else if (aEventMessage >= eDragDropEventFirst &&
                aEventMessage <= eDragDropEventLast) {
       CacheExternalDragFormats();
@@ -1356,7 +1359,7 @@ DataTransfer::CacheExternalDragFormats()
 }
 
 void
-DataTransfer::CacheExternalClipboardFormats()
+DataTransfer::CacheExternalClipboardFormats(bool aPlainTextOnly)
 {
   NS_ASSERTION(mEventMessage == ePaste,
                "caching clipboard data for invalid event");
@@ -1375,6 +1378,17 @@ DataTransfer::CacheExternalClipboardFormats()
   nsCOMPtr<nsIPrincipal> sysPrincipal;
   ssm->GetSystemPrincipal(getter_AddRefs(sysPrincipal));
 
+  if (aPlainTextOnly) {
+    bool supported;
+    const char* unicodeMime[] = { kUnicodeMime };
+    clipboard->HasDataMatchingFlavors(unicodeMime, 1, mClipboardType,
+                                      &supported);
+    if (supported) {
+      CacheExternalData(kUnicodeMime, 0, sysPrincipal, false);
+    }
+    return;
+  }
+
   // Check if the clipboard has any files
   bool hasFileData = false;
   const char *fileMime[] = { kFileMime };
diff --git a/dom/events/DataTransfer.h b/dom/events/DataTransfer.h
index 284edd56992c..729b23feb371 100644
--- a/dom/events/DataTransfer.h
+++ b/dom/events/DataTransfer.h
@@ -307,7 +307,7 @@ protected:
   void CacheExternalDragFormats();
 
   // caches the formats that exist in the clipboard
-  void CacheExternalClipboardFormats();
+  void CacheExternalClipboardFormats(bool aPlainTextOnly);
 
   FileList* GetFilesInternal(ErrorResult& aRv, nsIPrincipal* aSubjectPrincipal);
   nsresult GetDataAtInternal(const nsAString& aFormat, uint32_t aIndex,
diff --git a/editor/libeditor/HTMLEditorDataTransfer.cpp b/editor/libeditor/HTMLEditorDataTransfer.cpp
index 21a6948e1673..1d126fe09aeb 100644
--- a/editor/libeditor/HTMLEditorDataTransfer.cpp
+++ b/editor/libeditor/HTMLEditorDataTransfer.cpp
@@ -1495,7 +1495,7 @@ HTMLEditor::PasteTransferable(nsITransferable* aTransferable)
 NS_IMETHODIMP
 HTMLEditor::PasteNoFormatting(int32_t aSelectionType)
 {
-  if (!FireClipboardEvent(ePaste, aSelectionType)) {
+  if (!FireClipboardEvent(ePasteNoFormatting, aSelectionType)) {
     return NS_OK;
   }
 
diff --git a/widget/EventMessageList.h b/widget/EventMessageList.h
index a183253b5248..c4e42835663e 100644
--- a/widget/EventMessageList.h
+++ b/widget/EventMessageList.h
@@ -226,6 +226,7 @@ NS_EVENT_MESSAGE(eXULCommand)
 NS_EVENT_MESSAGE(eCopy)
 NS_EVENT_MESSAGE(eCut)
 NS_EVENT_MESSAGE(ePaste)
+NS_EVENT_MESSAGE(ePasteNoFormatting)
 
 // Query for the selected text information, it return the selection offset,
 // selection length and selected text.