1. Detect whether to support Paste
a. OlegetClipboard Removes IdataObject
b. Take DWEffectoffered from Idataobject
c. Detection support DROPEFFECT_MOPY | DROPEFFECT_COPY
d. Detection support supports DROPEFFECT_LINK (so 2 DrageNter Dragleave)
2. DROP
IdataObject Dragenter (DROPEFFECT_MOVE | DROPEFFECT_COPY | DROPEFFECT_LINK)
Drop
