[escher] ExpressionTableCell is composed of a ScrollableExpressionView

instead of an ExpressionView

apps/variable_box_controller.cpp

@@ -21,6 +21,9 @@ VariableBoxController::VariableBoxController() :
   m_lockPageDelete(Page::RootMenu),
   m_firstMemoizedLayoutIndex(0)
 {
+  for (int i = 0; i < k_maxNumberOfDisplayedRows; i++) {
+    m_leafCells[i].setParentResponder(&m_selectableTableView);
+  }
 }
 
 void VariableBoxController::viewWillAppear() {