diff --git a/src/mathed/InsetMathDecoration.cpp b/src/mathed/InsetMathDecoration.cpp
index a717484c05..1cb3aebcc1 100644
--- a/src/mathed/InsetMathDecoration.cpp
+++ b/src/mathed/InsetMathDecoration.cpp
@@ -22,6 +22,7 @@
 #include "LaTeXFeatures.h"
 
 #include "support/debug.h"
+#include "support/docstring.h"
 #include "support/lassert.h"
 
 #include <ostream>
@@ -105,7 +106,7 @@ InsetMath::mode_type InsetMathDecoration::currentMode() const
 void InsetMathDecoration::metrics(MetricsInfo & mi, Dimension & dim) const
 {
 	bool const upshape = currentMode() == TEXT_MODE
-				&& mi.base.font.color() == Color_math;
+				&& isMathFont(from_ascii(mi.base.fontname));
 	ShapeChanger dummy(mi.base.font, upshape ?
 				UP_SHAPE : mi.base.font.shape());
 
@@ -129,7 +130,7 @@ void InsetMathDecoration::metrics(MetricsInfo & mi, Dimension & dim) const
 void InsetMathDecoration::draw(PainterInfo & pi, int x, int y) const
 {
 	bool const upshape = currentMode() == TEXT_MODE
-				&& pi.base.font.color() == Color_math;
+				&& isMathFont(from_ascii(pi.base.fontname));
 	ShapeChanger dummy(pi.base.font, upshape ?
 				UP_SHAPE : pi.base.font.shape());
 
diff --git a/src/mathed/MathSupport.cpp b/src/mathed/MathSupport.cpp
index 99930ae4bd..7dc8bafa05 100644
--- a/src/mathed/MathSupport.cpp
+++ b/src/mathed/MathSupport.cpp
@@ -646,6 +646,13 @@ bool isFontName(docstring const & name)
 }
 
 
+bool isMathFont(docstring const & name)
+{
+	fontinfo * f = lookupFont(name);
+	return f && f->color_ == Color_math;
+}
+
+
 FontInfo getFont(docstring const & name)
 {
 	FontInfo font;
diff --git a/src/mathed/MathSupport.h b/src/mathed/MathSupport.h
index a2279991af..42d0977be1 100644
--- a/src/mathed/MathSupport.h
+++ b/src/mathed/MathSupport.h
@@ -49,6 +49,8 @@ void augmentFont(FontInfo & f, docstring const & cmd);
 
 bool isFontName(docstring const & name);
 
+bool isMathFont(docstring const & name);
+
 // converts single cell to string
 docstring asString(MathData const & ar);
 // converts single inset to string