package require tkdnd
dnd bindsource .perl_hlist_object text/uri {\&Perl_Sub}
bind .perl_hlist_object <1> {dnd drag %W}

##</code><code>##

my $mw = MainWindow->new;    #Gives me the main window object, but not the interpreter
my $interp = new Tcl::Tk;    #Gives me the interpreter, but not the main window

##</code><code>##

My $i = new Tcl::Tk;
(... generate GUI ...)
$i -> call("package require", "tkdnd");
$i -> call("dnd bindsource", ".perl_hlist_object", "text/uri", {\&Perl_Sub});
$i -> call("bind", ".perl_hlist_object", "<1>", {dnd drag %W};