Closes #2236

I am not sure if this restriction for non-differentiate is at the right place, but I could not find any better.

chapters/synchronous.tex

@@ -855,6 +855,9 @@ \subsection{Sub-clock conversion operators}\doublelabel{sub-clock-conversion-ope
 limit). However, y will show the current value, since it has no
 infinitesimal delay.{]}}
 
+Note that it is not legal to compute the derivative of the \lstinline!sample!, \lstinline!subSample!, \lstinline!superSample!, \lstinline!backSample!,
+\lstinline!shiftSample!, and \lstinline!noClock! operators. 
+
 \section{Clocked When Clause}\doublelabel{clocked-when-clause}
 
 In addition to the previously discussed conditional when-clause, a
@@ -1141,6 +1144,7 @@ \section{Continuous-Time Equations in Clocked Partitions}\doublelabel{continuous
 partitions. Hereby, a discretized continuous-time partition is seen as a
 clocked partition.
 
+
 \subsection{Clocked Discrete-Time and Clocked Discretized Continuous-Time Partition}\doublelabel{clocked-discrete-time-and-clocked-discretized-continuous-time-partition}
 
 Additionally to the variability of expressions defined in \autoref{variability-of-expressions},