Creates a widget that can be used as a drag icon for the given value.
Supported types include strings, `GdkRGBA` and `GtkTextBuffer`. If GTK does not know how to create a widget for a given value, it will return null.
This method is used to set the default drag icon on drag-and-drop operations started by `GtkDragSource`, so you don't need to set a drag icon using this function there.
| value |
a `GValue` |
|
A new `GtkWidget` for displaying |