Initialize handles mouse down value when selection mode is false.

Initialize handles mouse down value when selection mode is false.

[Title] Initialize handles mouse down value when selection mode is false.
[Issue#] N_SE-36670
[Problem] Context menu isn't disapper when longpressed on handle in Interner-ref
[Cause] There is no initialize code for handles mouse down value. So it ignored longpress event happend from handles.
[Solution] Add handles mousedown value initialize code.

Change-Id: I5040827fc416872f92d93c44d033716c69ec14e8