Transparent windows: how to get rid of it?

[Colin Law]

On 29 November 2011 21:12, Freddy Van Ingelgom <freddyek at gmail.com> wrote:
> I use Ubuntu 11.10 with Unity as interface. Ican not say that I was always
> happy with this Unity thing, but I like it now. There is one thing I hate:
> from time to time there is a sort of transparent window appearing on the
> screen and I can not find a way to get rid of it! I would like to know what
> the purpose of this "window" is, what triggers the appearance of this
> window, and most of all: is there a way to switch this "feature" off?
> Any help is most appreciated!

Can you give us a clue as to what is on this window?  If not then
perhaps a screenshot.

Colin