diff --git a/src/insets/InsetIndex.cpp b/src/insets/InsetIndex.cpp
index 94d2a961bc..11c3a26fd0 100644
--- a/src/insets/InsetIndex.cpp
+++ b/src/insets/InsetIndex.cpp
@@ -54,9 +54,9 @@ int InsetIndex::latex(odocstream & os,
 	odocstringstream ods2;
 	InsetText::plaintext(ods2, runparams);
 	std::vector<docstring> const levels =
-		getVectorFromString(ods.str(), from_ascii("!"));
+		getVectorFromString(ods.str(), from_ascii("!"), true);
 	std::vector<docstring> const levels_plain =
-		getVectorFromString(ods2.str(), from_ascii("!"));
+		getVectorFromString(ods2.str(), from_ascii("!"), true);
 	vector<docstring>::const_iterator it = levels.begin();
 	vector<docstring>::const_iterator end = levels.end();
 	vector<docstring>::const_iterator it2 = levels_plain.begin();
@@ -71,9 +71,13 @@ int InsetIndex::latex(odocstream & os,
 		// e.g. \index{LyX@\LyX}, \index{text@\textbf{text}}
 		// Don't do that if the user entered '@' himself, though.
 		if (contains(*it, '\\') && !contains(*it, '@')) {
+			// Plaintext might return nothing (e.g. for ERTs)
+			docstring spart =
+				(it2 < levels_plain.end()
+				 && !(*it2).empty()) ? *it2 : *it;
 			// remove remaining \'s for the sorting part
 			docstring const ppart =
-				subst(*it2, from_ascii("\\"), docstring());
+				subst(spart, from_ascii("\\"), docstring());
 			os << ppart;
 			os << '@';
 			i += ppart.size() + 1;
diff --git a/src/support/lstrings.cpp b/src/support/lstrings.cpp
index 32629481b1..6792cf6bcd 100644
--- a/src/support/lstrings.cpp
+++ b/src/support/lstrings.cpp
@@ -913,7 +913,7 @@ docstring const escape(docstring const & lab)
 namespace {
 
 template<typename String> vector<String> const
-getVectorFromStringT(String const & str, String const & delim)
+getVectorFromStringT(String const & str, String const & delim, bool keepempty)
 {
 // Lars would like this code to go, but for now his replacement (below)
 // doesn't fullfil the same function. I have, therefore, reactivated the
@@ -930,7 +930,7 @@ getVectorFromStringT(String const & str, String const & delim)
 			break;
 		}
 		String const key = trim(keys.substr(0, idx));
-		if (!key.empty())
+		if (!key.empty() || keepempty)
 			vec.push_back(key);
 		size_t const start = idx + delim.size();
 		keys = keys.substr(start);
@@ -949,16 +949,18 @@ getVectorFromStringT(String const & str, String const & delim)
 
 
 vector<string> const getVectorFromString(string const & str,
-					 string const & delim)
+					 string const & delim,
+					 bool keepempty)
 {
-	return getVectorFromStringT<string>(str, delim);
+	return getVectorFromStringT<string>(str, delim, keepempty);
 }
 
 
 vector<docstring> const getVectorFromString(docstring const & str,
-					    docstring const & delim)
+					    docstring const & delim,
+					    bool keepempty)
 {
-	return getVectorFromStringT<docstring>(str, delim);
+	return getVectorFromStringT<docstring>(str, delim, keepempty);
 }
 
 
diff --git a/src/support/lstrings.h b/src/support/lstrings.h
index c9bc75a9a7..01f72383ae 100644
--- a/src/support/lstrings.h
+++ b/src/support/lstrings.h
@@ -225,10 +225,12 @@ std::string const rsplit(std::string const & a, std::string & piece, char delim)
 docstring const escape(docstring const & lab);
 
 /// gives a vector of stringparts which have the delimiter delim
+/// If \p keepempty is true, empty strings will be pushed to the vector as well
 std::vector<std::string> const getVectorFromString(std::string const & str,
-					      std::string const & delim = std::string(","));
+					      std::string const & delim = std::string(","),
+					      bool keepempty = false);
 std::vector<docstring> const getVectorFromString(docstring const & str,
-		docstring const & delim = from_ascii(","));
+		docstring const & delim = from_ascii(","), bool keepempty = false);
 
 // the same vice versa
 std::string const getStringFromVector(std::vector<std::string> const & vec,