+For orientation of the book controller, use following flags in style:
+\twocolwidtha{5cm}
+\begin{twocollist}\itemsep=0pt
+\twocolitem{\windowstyle{wxBK\_TOP}}{controller above pages}
+\twocolitem{\windowstyle{wxBK\_BOTTOM}}{controller below pages}
+\twocolitem{\windowstyle{wxBK\_LEFT}}{controller on the left}
+\twocolitem{\windowstyle{wxBK\_RIGHT}}{controller on the right}
+\twocolitem{\windowstyle{wxBK\_DEFAULT}}{native controller placement}
+\end{twocollist}