lib/texinputs/isabelle.sty

--- a/lib/texinputs/isabelle.sty	Sat Feb 03 15:34:22 2018 +0100
+++ b/lib/texinputs/isabelle.sty	Sat Feb 03 20:34:26 2018 +0100
@@ -239,7 +239,7 @@
 % cancel text
 
 \usepackage[normalem]{ulem}
-\newcommand{\isamarkupcancel}[1]{\xout{#1}}
+\newcommand{\isamarkupcancel}[1]{\isa{\xout{#1}}}
 
 
 % tagged regions