diff --git a/src/frontends/qt4/FindAndReplace.cpp b/src/frontends/qt4/FindAndReplace.cpp
index 500514a558..9c8bf1e12e 100644
--- a/src/frontends/qt4/FindAndReplace.cpp
+++ b/src/frontends/qt4/FindAndReplace.cpp
@@ -119,7 +119,6 @@ void FindAndReplaceWidget::findAndReplace(
 			searchString += it->stringify(pos_type(0), it->size(), AS_STR_INSETS, runparams);
 		}
 	}
-//	lyxerr << "Searching for '" << to_utf8(searchString) << "'" << std::endl;
 	if (to_utf8(searchString).empty()) {
 		buffer.message(_("Nothing to search"));
 		return;
@@ -132,6 +131,16 @@ void FindAndReplaceWidget::findAndReplace(
 	} else {
 		replaceString = from_utf8(LYX_FR_NULL_STRING);
 	}
+	LYXERR(Debug::DEBUG, "FindAndReplaceOptions: "
+	       << "searchstring=" << searchString
+	       << ", casesensitiv=" << casesensitive
+	       << ", matchword=" << matchword
+	       << ", backwards=" << backwards
+	       << ", expandmacros=" << expandmacros
+	       << ", ignoreformat=" << ignoreformat
+	       << ", regexp=" << regexp
+	       << ", replaceString" << replaceString
+	       << std::endl);
 	FindAndReplaceOptions opt(searchString, casesensitive, matchword, ! backwards,
 		expandmacros, ignoreformat, regexp, replaceString);
 	LYXERR(Debug::DEBUG, "Dispatching LFUN_WORD_FINDADV" << std::endl);
diff --git a/src/lyxfind.cpp b/src/lyxfind.cpp
index 1002a01d09..750eb90d8a 100644
--- a/src/lyxfind.cpp
+++ b/src/lyxfind.cpp
@@ -507,7 +507,7 @@ size_t find_matching_brace(string const & s, size_t pos)
 	return s.size();
 }
 
-/// Within \regex{} apply get_regex_escapes(), while outside apply get_lyx_unescapes().
+/// Within \regexp{} apply get_regex_escapes(), while outside apply get_lyx_unescapes().
 string escape_for_regex(string s)
 {
 	size_t pos = 0;
@@ -596,9 +596,6 @@ bool braces_match(string::const_iterator const & beg,
 }
 
 /** The class performing a match between a position in the document and the FindAdvOptions.
- **
- ** @todo The user-entered regexp expression(s) should be enclosed within something like \regexp{},
- **       to be written by a dedicated Inset, so to avoid escaping it in escape_for_regex().
  **/
 class MatchStringAdv {
 public:
@@ -768,8 +765,9 @@ string MatchStringAdv::normalize(docstring const & s) const
 	while ((pos = t.find("\n")) != string::npos)
 		t.replace(pos, 1, " ");
 	// Remove stale empty \emph{}, \textbf{} and similar blocks from latexify
-	while (regex_replace(t, t, "\\\\[a-zA-Z_]+(\\{\\})+", ""))
-		;
+	LYXERR(Debug::DEBUG, "Removing stale empty \emph{}, \textbf{} macros from: " << t);
+	while (regex_replace(t, t, "\\\\(emph|textbf)(\\{\\})+", ""))
+		LYXERR(Debug::DEBUG, "  further removing stale empty \emph{}, \textbf{} macros from: " << t);
 	return t;
 }
 
diff --git a/src/mathed/InsetMathHull.cpp b/src/mathed/InsetMathHull.cpp
index d22203816f..8b85e064fc 100644
--- a/src/mathed/InsetMathHull.cpp
+++ b/src/mathed/InsetMathHull.cpp
@@ -1671,8 +1671,11 @@ int InsetMathHull::plaintext(odocstream & os, OutputParams const & runparams) co
 	} else {
 		odocstringstream oss;
 		WriteStream wi(oss, false, true, WriteStream::wsDefault, runparams.encoding);
-		wi << cell(0);
-
+		// Fix Bug #6139
+		if (type_ == hullRegexp)
+			write(wi);
+		else
+			wi << cell(0);
 		docstring const str = oss.str();
 		os << str;
 		return str.size();