By default, the control displays no splitters. Use the AllowSplitter property to add or remove the control's splitters. A splitter splits the expression control in panes. Use the SplitPaneWidth property to horizontally split the control. Use the SplitPaneHeight property to vertically split the control. The SplitterChange event notifies your application that the control's splitter is changed. Use the FocusPane property to specify the pane that has the focus.