onDragBegin
fun onDragBegin( connectFlags: <Error class: unknown class> = ConnectFlags(0u), handler: (<Error class: unknown class>, <Error class: unknown class>) -> Unit): <Error class: unknown class>(source)
Emitted whenever dragging starts.
Parameters
connectFlags
a combination of ConnectFlags
handler
the Callback to connect. Params: startX X coordinate, relative to the widget allocation; startY Y coordinate, relative to the widget allocation