diff --git a/lib/scripts/lyxpreview2bitmap.py b/lib/scripts/lyxpreview2bitmap.py
index a7d76236fb..c2b94d4ed5 100755
--- a/lib/scripts/lyxpreview2bitmap.py
+++ b/lib/scripts/lyxpreview2bitmap.py
@@ -160,7 +160,7 @@ def extract_metrics_info(dvipng_stdout):
 
 def fix_latex_file(latex_file, pdf_output):
     documentclass_re = re.compile("(\\\\documentclass\[)(1[012]pt,?)(.+)")
-    def_re = re.compile(r"(\\newcommandx|\\global\\long\\def)(\\[a-zA-Z])(.+)")
+    def_re = re.compile(r"(\\newcommandx|\\global\\long\\def)(\\[a-zA-Z]+)(.+)")
     usepackage_re = re.compile("\\\\usepackage")
     userpreamble_re = re.compile("User specified LaTeX commands")
     enduserpreamble_re = re.compile("\\\\makeatother")
diff --git a/src/mathed/InsetMathHull.cpp b/src/mathed/InsetMathHull.cpp
index 4e18b72420..0cfaad0dc0 100644
--- a/src/mathed/InsetMathHull.cpp
+++ b/src/mathed/InsetMathHull.cpp
@@ -647,6 +647,10 @@ void InsetMathHull::usedMacros(MathData const & md, DocIterator const & pos,
 			if (macros.find(name) == end)
 				continue;
 			macros.erase(name);
+			// Look for macros in the arguments of this macro.
+			for (idx_type idx = 0; idx < mi->nargs(); ++idx)
+				usedMacros(mi->cell(idx), pos, macros, defs);
+			// Look for macros in the definition of this macro.
 			MathData ar(pos.buffer());
 			MacroData const * data =
 				pos.buffer()->getMacro(name, pos, true);