--- a/dom/base/nsDocumentEncoder.cpp
+++ b/dom/base/nsDocumentEncoder.cpp
@@ -1391,27 +1391,22 @@ nsHTMLCopyEncoder::SetSelection(nsISelec
       break;
     }
     else if (selContent->IsElement()) {
       nsRefPtr<nsStyleContext> styleContext =
         nsComputedDOMStyle::GetStyleContextForElementNoFlush(selContent->AsElement(),
                                                              nullptr, nullptr);
       if (styleContext) {
         const nsStyleText* textStyle = styleContext->StyleText();
-        switch (textStyle->mWhiteSpace) {
-        case NS_STYLE_WHITESPACE_PRE:
-        case NS_STYLE_WHITESPACE_PRE_WRAP:
-        case NS_STYLE_WHITESPACE_PRE_LINE:
-        case NS_STYLE_WHITESPACE_PRE_SPACE:
+        if (textStyle->WhiteSpaceOrNewlineIsSignificant()) {
           // Copy as plaintext for all preformatted elements
           mIsTextWidget = true;
-          break;
         }
+        break;
       }
-      break;
     }
   }
   
   // normalize selection if we are not in a widget
   if (mIsTextWidget) 
   {
     mSelection = aSelection;
     mMimeType.AssignLiteral("text/plain");