I'm sometimes asked by developers "How do I make un-associated (gray) data disappear from listboxes?". After some discussion as to why they want to do this, I usually attempt to convince them to not hide any data.
Gray data is an important part of the power of Qlikview -- the associative experience. Associative is the way our mind connects data. When I try to recall a face I may narrow my candidates by an attribute like hair color or where we met. But I don't forget everyone else. I just take them out of focus.
I recall one of my first Qlikview "Wow!" moments when I saw the power of the associative process. I was working with a Industrial Safety analyst who was studying the effectiveness of various glove styles in preventing hand injuries. We had a database of injuries and a separate dataset of glove models in use by period and location.
Up to this point, the analyst had been working from static reports that counted injuries of interest by looking for "where BodyPart='Hand'".
We loaded the data into Qlikview. BodyPart became a listbox. He selected "Hand" and the table charts displayed the same counts as the static reports. In the gray data we noticed a significant number of injuries for "Hend", a misspelling of "Hand". A simple click added those into the total. The analyst also discovered "finger" and "fingers" were of interest and added those. Furthermore, for certain glove styles -- those with a gauntlet sleeve -- "forearm" should be added.
With just a few clicks the Analyst had greater accuracy in this important work. It was the display of gray data that allowed this to happen, along with the ability to quickly convert gray to green (selected).
So while there may be edge cases where it's necessary to hide gray data, I generally find that displaying all data in the associative manner is a unique and special advantage of Qlikview.