diff --git a/src/mathed/InsetMathCases.cpp b/src/mathed/InsetMathCases.cpp
index 1b5df8dc9f..88012aa247 100644
--- a/src/mathed/InsetMathCases.cpp
+++ b/src/mathed/InsetMathCases.cpp
@@ -185,4 +185,10 @@ void InsetMathCases::validate(LaTeXFeatures & features) const
 }
 
 
+int InsetMathCases::displayColSpace(col_type) const
+{
+	return 20;
+}
+
+
 } // namespace lyx
diff --git a/src/mathed/InsetMathCases.h b/src/mathed/InsetMathCases.h
index f753f12166..7820922f07 100644
--- a/src/mathed/InsetMathCases.h
+++ b/src/mathed/InsetMathCases.h
@@ -52,6 +52,8 @@ public:
 	void validate(LaTeXFeatures & features) const;
 	///
 	InsetCode lyxCode() const { return MATH_CASES_CODE; }
+	///
+	int displayColSpace(col_type) const;
 private:
 	virtual Inset * clone() const;
 };