Hello, I'm currently developing a feature using C# for Autodesk Civil 3D, and I'm wondering if there's a way to detect when the ObjectViewer window is closed. Here's what I'm trying to accomplish: My entities are initially on a layer that is turned off. When the user runs the command, I turn on the necessary layers, select the target entities, and open them in ObjectViewer using SendStringToExecute("._OBJECTVIEWER\n", ...). Once the ObjectViewer is closed by the user, I want to automatically turn off the layers again. The problem is that I don't know how to detect when the ObjectViewer closes. I've tried using CommandEnded or CommandWillStart, but they don’t seem to trigger when ObjectViewer is closed. Is there any event or even indirect method to detect when ObjectViewer has been closed? Any suggestions would be greatly appreciated. Thank you!