+ among them yap, xdvi, okular
+\begin_inset Foot
+status open
+
+\begin_layout Plain Layout
+You might want to set
+\begin_inset Flex Code
+status collapsed
+
+\begin_layout Plain Layout
+okular --unique
+\end_layout
+
+\end_inset
+
+ in
+\begin_inset Flex MenuItem
+status collapsed
+
+\begin_layout Plain Layout
+Tools\SpecialChar \menuseparator
+Preferences\SpecialChar \menuseparator
+File Handling\SpecialChar \menuseparator
+File
+\begin_inset space ~
+\end_inset
+
+Formats
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+
+ and Sumatra PDF