This line will display the Control Panel folder in the TJamShellList:

JamShellList.SpecialFolder := SF_CONTROLS;

The following example shows the properties dialog for all selected items, if the listed folder is a file system folder. This allows the user to see the summarized size of all items.

With JamShellList do
if SpecialFolder = SF_FILESYSTEM then begin
  SelectAll();
  InvokeCommandOnSelected('properties');
end;