The dialog appears when you right-click a tabular cell and click button on the toolbar or click Menu > Format > Split. It helps you to specify the number of rows and columns that the specified tabular cell will be split into. See the dialog.
Split Cell Into
Specifies the number of rows and columns to split the selected tabular cell into.
OK
Closes this dialog and splits the tabular cell.
Cancel
Cancels to split the cell and closes this dialog.
Help
Displays this help document.