<p>I've made a custom DataGridViewCell that displays a custom control instead of the cell; but if the DataGridView uses shared rows, then the custom control instance is also shared, so you get strange behaviour (for example, hovering over buttons highlights all the buttons).  Also, I can't access the DataGridViewCell.Selected property, so I don't know what colour to paint the row.</p>

<p>How do I prevent a DataGridView from sharing rows?  I know I can add the rows using the Rows.Add(object[]) override, but then the first row is still shared (i.e. has index -1) so the problem with colours still applies.</p>

<p>I need to be able to tell the DataGridView not to share a row containing a custom cell.  Can that be done with attributes?  Can it be done at all?</p>

Try to set a Tooltip Text in one cell of the Row
A row cannot be shared in any of the following situations: 
 The row contains a single selected cell that is not in a selected column. 
 The row contains a cell with its ToolTipText or ContextMenuStrip properties set. 
 The row contains a DataGridViewComboBoxCell with its Items property set.
or read
http://msdn.microsoft.com/en-us/library/ha5xt0d9.aspx
for more Information