--- a/widget/windows/nsClipboard.cpp
+++ b/widget/windows/nsClipboard.cpp
@@ -104,18 +104,18 @@ UINT nsClipboard::GetFormat(const char* 
            strcmp(aMimeStr, kJPGImageMime) == 0 ||
            strcmp(aMimeStr, kPNGImageMime) == 0) {
     format = CF_DIBV5;
   }
   else if (strcmp(aMimeStr, kFileMime) == 0 ||
            strcmp(aMimeStr, kFilePromiseMime) == 0) {
     format = CF_HDROP;
   }
-  else if (strcmp(aMimeStr, kNativeHTMLMime) == 0 ||
-           aMapHTMLMime && strcmp(aMimeStr, kHTMLMime) == 0) {
+  else if ((strcmp(aMimeStr, kNativeHTMLMime) == 0) ||
+           (aMapHTMLMime && strcmp(aMimeStr, kHTMLMime) == 0)) {
     format = CF_HTML;
   }
   else if (strcmp(aMimeStr, kCustomTypesMime) == 0) {
     format = CF_CUSTOMTYPES;
   }
   else {
     format = ::RegisterClipboardFormatW(NS_ConvertASCIItoUTF16(aMimeStr).get());
   }