Vibrating display on Edge and IE, 0.9.10-11

[Hiroki Niinuma]

Hi All.

After 0.9.10,
IE11 or Edge recent,
RDP, Recconect,
set some text clipboard's textarea,

And guac menu open-close, display is vibrating.

As other problems around the clipboard on these browser,
exec "copy" didn't work.

Thanks.

Niinuma