Often when one selects a package for installation or removal in gpk-application, the package list is greyed out to indicate that the user can't/shouldn't do anything while some background operation is in progress.
The downside is that in many cases selecting a package results in a somewhere between 0.5sec and 1sec of background work and grey screen comes up and vanishes quickly, resulting in what seems looks like flashing.
It can be annoying.
On the other hand, this graying out as an indication of background work is in general a very good idea compared to, say, Synaptic, where one selects a package and then there is no explicit response and no indication that the app is working and didn't hung at the same time.
We don't do this anymore in 2.27.9x -- if you try the Fedora 12 alpha live CD you'll see what I mean. Thanks.