Inventory GUI vs World editor(Canvas) for TGE 1.4

Hi All,

Yeah I know its possible with TGEA 1.7, but I am trying to add with TGE 1.4,
is not it possible for TGE1.4.

Basically I need an interface which can do the task like drag-n-drop items from
the Inventory GUI to the World terrain by mouse.
Wd you please suggest me from where to start to implement those interface??
So say you drag it out to the top of the
screen and let go, it would fly hard and high, if you dragged it to
the bottom it would be thrown at their feet.

Its possible by the key board when Inventory GUI is not top of the screen. But whenever
its toggled neither keyboard nor mouse is working.. How can I enable my mouse so that
I can drop items by dragging those from Inventory to the World Canvas..
I need to do this with TGE 1.4 only..
Please suggest me some.
Thank you lot in advance.

Thanks & Regards
Ryan.