I posted this in User Interface, but I am trying to do this through API. When I do a replace in SolidWorks, after the replace I am presented with a What’s Wrong dialog, and a Mated Entities Property Manager that has a Disable/Enable Preview button that will show a small window with the component/mate selected. If I finish and then select "Replace Mate Entities" on a component, I get the same Mated Entities Property Manager but this time WITHOUT the Disable/Enable Preview button. I can make this happen through API by programmatically selecting components and then call m_objiSwApp.RunCommand((int)swCommands_e.swCommands_View_Mates but still DO NOT get preview button. If anyone knows how to have preview button show I would appreciate. Thanks in advance Scott Cleveland