\begin{scope}[node distance=0.75cm]

\node (Stk0) [draw, shape=rectangle, minimum width=1.5cm, minimum height=0.75cm, anchor=center]
  at (-2.75, 0)     {shift};
\node (Stk1) [draw, shape=rectangle, minimum width=1.5cm, minimum height=0.75cm, anchor=center]
  at (-2.75, -0.75) {foo};
\node (Stk2) [draw, shape=rectangle, minimum width=1.5cm, minimum height=0.75cm, anchor=center]
  at (-2.75, -1.5)  {bar};
\node (Stk3) [draw, shape=rectangle, minimum width=1.5cm, minimum height=0.75cm, anchor=center]
  at (-2.75, -2.25) {reset};
\node (Stk3) [draw, shape=rectangle, minimum width=1.5cm, minimum height=0.75cm, anchor=center]
  at (-2.75, -3)  {baz};
\draw [red, very thick, dashed] (-3.6, -2.625) -- (-1.89, -2.625) -- (-1.89, 0.375) -- (-3.6, 0.375) -- cycle;
\draw [arrows={Latex}-] (-4, 0.375) -- (-4, -3.375);
\end{scope}