diff --git a/src/tex2lyx/TODO.txt b/src/tex2lyx/TODO.txt
index cafa32226a..e625d83ac9 100644
--- a/src/tex2lyx/TODO.txt
+++ b/src/tex2lyx/TODO.txt
@@ -97,4 +97,9 @@ Format LaTeX feature                        LyX feature
 409    XeTeX                                \use_non_tex_fonts
 411    babel etc.                           \language_package
 412    tabular*                             InsetTabular
+414    \textvisiblespace                    InsetSpace
+415    undertilde.sty                       fonts
+416    \negmedspace, \negthinspace          InsetSpace
+416    \hfill, \enspace, \hspace*,          InsetMathSpace
+       \hspace*{\fill}
 
diff --git a/src/tex2lyx/preamble.cpp b/src/tex2lyx/preamble.cpp
index 0ead8d4a76..a6861b490b 100644
--- a/src/tex2lyx/preamble.cpp
+++ b/src/tex2lyx/preamble.cpp
@@ -206,6 +206,7 @@ string h_use_amsmath             = "1";
 string h_use_esint               = "1";
 string h_use_mhchem              = "0";
 string h_use_mathdots            = "0";
+string h_use_undertilde          = "0";
 string h_cite_engine             = "basic";
 string h_use_bibtopic            = "false";
 string h_paperorientation        = "portrait";
@@ -518,6 +519,9 @@ void handle_package(Parser &p, string const & name, string const & opts,
 	else if (name == "mathdots")
 		h_use_mathdots = "2";
 
+	else if (name == "undertilde")
+		h_use_undertilde = "2";
+
 	else if (name == "babel" && !opts.empty()) {
 		// check if more than one option was used - used later for inputenc
 		// in case inputenc is parsed before babel, set the encoding to auto
@@ -748,6 +752,7 @@ void end_preamble(ostream & os, TextClass const & /*textclass*/)
 	   << "\\use_esint " << h_use_esint << "\n"
 	   << "\\use_mhchem " << h_use_mhchem << "\n"
 	   << "\\use_mathdots " << h_use_mathdots << "\n"
+	   << "\\use_undertilde " << h_use_undertilde << "\n"
 	   << "\\cite_engine " << h_cite_engine << "\n"
 	   << "\\use_bibtopic " << h_use_bibtopic << "\n"
 	   << "\\paperorientation " << h_paperorientation << '\n'
diff --git a/src/tex2lyx/tex2lyx.h b/src/tex2lyx/tex2lyx.h
index 7101a7c7f8..22bc903bc4 100644
--- a/src/tex2lyx/tex2lyx.h
+++ b/src/tex2lyx/tex2lyx.h
@@ -166,7 +166,7 @@ extern bool noweb_mode;
 /// Did we recognize any pdflatex-only construct?
 extern bool pdflatex;
 /// LyX format that is created by tex2lyx
-int const LYX_FORMAT = 413;
+int const LYX_FORMAT = 416;
 
 /// path of the master .tex file
 extern std::string getMasterFilePath();