diff --git a/mozilla/layout/base/nsCSSFrameConstructor.cpp b/mozilla/layout/base/nsCSSFrameConstructor.cpp
index 3305274a437..71f1ff3ddbc 100644
--- a/mozilla/layout/base/nsCSSFrameConstructor.cpp
+++ b/mozilla/layout/base/nsCSSFrameConstructor.cpp
@@ -6783,7 +6783,7 @@ nsCSSFrameConstructor::ConstructMathMLFrame(nsFrameConstructorState& aState,
     
     nsRefPtr<nsStyleContext> blockContext;
     blockContext = styleSet->ResolvePseudoStyleFor(aContent,
-                                                   nsCSSAnonBoxes::mozAnonymousBlock,
+                                                   nsCSSAnonBoxes::mozMathMLAnonymousBlock,
                                                    mrowContext);
     
     // then, create a block frame that will wrap the table frame
diff --git a/mozilla/layout/mathml/content/src/mathml.css b/mozilla/layout/mathml/content/src/mathml.css
index ef1e461c783..09a417cdb0a 100644
--- a/mozilla/layout/mathml/content/src/mathml.css
+++ b/mozilla/layout/mathml/content/src/mathml.css
@@ -472,3 +472,12 @@ mtd[-moz-math-columnline="dashed"] {
 semantics > :not(:first-child) {
   display: none;
 }
+
+/**
+ * Temporary, until we make mtable no longer use display: table
+ */
+*|*::-moz-mathml-anonymous-block {
+  display: block !important;
+  position: static !important;
+}
+
diff --git a/mozilla/layout/style/nsCSSAnonBoxList.h b/mozilla/layout/style/nsCSSAnonBoxList.h
index 9207f209c7f..07546027a7c 100644
--- a/mozilla/layout/style/nsCSSAnonBoxList.h
+++ b/mozilla/layout/style/nsCSSAnonBoxList.h
@@ -56,6 +56,7 @@ CSS_ANON_BOX(mozNonElement, ":-moz-non-element")
 
 CSS_ANON_BOX(mozAnonymousBlock, ":-moz-anonymous-block")
 CSS_ANON_BOX(mozAnonymousPositionedBlock, ":-moz-anonymous-positioned-block")
+CSS_ANON_BOX(mozMathMLAnonymousBlock, ":-moz-mathml-anonymous-block")
 
 CSS_ANON_BOX(mozLineFrame, ":-moz-line-frame")