Whether the drop data should be preloaded when the pointer is only hovering over the widget but has not been released.
Setting this property allows finer grained reaction to an ongoing drop at the cost of loading more data.
The default value for this property is
FALSE to avoid downloading
huge amounts of data by accident.
For example, if somebody drags a full document of gigabytes of text from a text editor across a widget with a preloading drop target, this data will be downloaded, even if the data is ultimately dropped elsewhere.
For a lot of data formats, the amount of data is very small (like
GDK_TYPE_RGBA), so enabling this property does not hurt at all.
And for local-only Drag-and-Drop operations, no data transfer is done,
so enabling it there is free.