Dbgrid1 adds a checkbox in the first line to determine the multiple choice?

Dbgrid1 adds a checkbox in the first line to determine the multiple choice? Delphi/Windows SDK/API
Http://www.delphi2007.net/DelphiMultimedia/html/delphi_2006120616261784.html
Add a checkbox in the first column. If it is checked, it is selected. If it is not checked, there is no such third-party control. No CodeThank you for implementing this function. (Note: it can be used when multiple data sources are selected ).

Dbgrideh control (ehlib control package) with checkbox

How to use it? You cannot add it to the first column. Creating a new column only shows the checkbox, but it cannot be used at all. Please advise;