Crash when a video is dragged into an empty queue

[JoseBritto]

Screencast from 2024-04-26 17-58-15.webm

Logs:

(clapper:2): Gtk-CRITICAL **: 18:02:03.799: gtk_widget_set_margin_top: assertion 'GTK_IS_WIDGET (widget)' failed

(clapper:2): Gtk-CRITICAL **: 18:02:03.804: gtk_widget_set_margin_bottom: assertion 'GTK_IS_WIDGET (widget)' failed

(clapper:2): Gtk-CRITICAL **: 18:02:04.786: gtk_widget_get_first_child: assertion 'GTK_IS_WIDGET (widget)' failed

(clapper:2): Gtk-CRITICAL **: 18:02:04.786: gtk_widget_set_margin_top: assertion 'GTK_IS_WIDGET (widget)' failed

(clapper:2): Gtk-CRITICAL **: 18:02:04.786: gtk_widget_set_margin_bottom: assertion 'GTK_IS_WIDGET (widget)' failed