title: multiple checkbox click events
body: <p>I have code that checks if every checkbox in a cell has been checked and if so changes the cells background color accordingly.</p>
  
  <p>I have a sheet with 900 ActiveX check boxes on, with 18 check boxes per cell,  and more may be added, i don't want to have to write 900 plus 'Private Sub CheckBox#_Click()' events.  Is there a way to write once event for all of them?</p>