OpenEuphoria

I don't understand what you meant there. You don't "run" widgets, and you don't put code "in" them. You tell the gui to create them, and you create event handlers that the gui calls when a widget sends an event. Any code that the widgets "have" is in the widget library and the individual widget class libraries, not in your application. You can create multiple instances of things, as long as each widget has a unique name ("winDownload1", winDownload2", etc.). Because widget names are strings, you can use normal string handling techniques to deal with them.