+todo in math mode

todos.sty

@@ -11,13 +11,14 @@
 \usepackage{xcolor} 
 \usepackage{ifdraft}    %% For access to the draft/final option of the documentclass
 
-\def\todo#1{}
+\def\todo#1{} % undefine, if defined previously
 
 \ifdraft
 {
+  \def\ensuretext#1{\ifmmode\text{#1}\else{#1}\fi}
   \def\todo{\@ifstar\@@todo\@todo}
   \ifpdf
-    \long\def\@todo#1{{\ttfamily\color[RGB]{255,64,64}TODO: #1}}
+    \long\def\@todo#1{\ensuretext{\ttfamily\color[RGB]{255,64,64}TODO: #1}}
     \long\def\@@todo#1{{\hfill\\\noindent\ttfamily\color[RGB]{255,64,64}TODO: #1\hfill\\[1ex]}}
   \else
   \fi