When an add-in displays a dialog box, the add-in needs to keep the dialog box in front of whatever window launched it. Failure to do so may result in the dialog box disappearing and the user becoming confused.
To keep the dialog box in the foreground, you can specify a parent window handle when the new dialog box is created.
Window handling is supported in SOLIDWORKS PDM Professional 6.4 and later. In SOLIDWORKS PDM Professional 6.4 only, you must also enable the Multithreaded Add-ins Threading policy.
Unlike Visual Basic 6, VB.NET and C# allow you to create add-in modules that support multi-threading. When SOLIDWORKS PDM Professional runs a multi-threaded NET add-in, it executes it in the same thread as the parent window. Calls to IEdmVault5::SetAddInWnd, which were previously recommended for Visual Basic 6, are no longer necessary.
To keep an add-in window in the foreground, call IEdmVault8::GetWin32Window in the .NET form of your add-in to specify the handle of the parent window.