title: Catching click event only in combobox's editable area
body: <p>I am trying to use a C# WinForms combobox in the following manner:</p>
  
  <p>a) regular use: if the "Down arrow" button is pressed, the dropdown area opens and the user selects the desired item - no problem there..</p>
  
  <p>b) advanced use: if the user clicks into the editable are of the dropdown control, another dialog with advanced selection mechanisms opens.</p>
  
  <p>Currently, I am calling the advanced dialog in the combobox's onclick event handler. However, now the regular use of the DropDownbox is not usable any more. The advanced dialog is opend even if you click only on the dropdown arrow.</p>
  
  <p>I couldn't find another likely event that I could use, so I assume that I have to check in the eventhandler if the user clicked into the control's editable part or on the control's button. Any ideas how to do that effectivly?</p>
  
  <p>Thanks for all hints.</p>