If I understood you correctly, you need to detect when the users clicks on an empty region of the grid? even if the grid is not empty?
If that is the case, you can simply subscribe to the “Click” even of the grid. that event would not be raised when the users clicks on a row or a header and it would only be raised when clicking on an empty space in the grid.
For example, if you open the samples of the grid live explorer , open the DynamicEditorDisplay sample, add the click event at the end of the DynamicEditorDisplay_Load event
gridControl1.Click += new EventHandler(gridControl1_Click);