I tend to like to have different libraries for different activities. For example, one for a mail archive, one for web clippings, etc. The problem is that for frequently used libraries such as web clippings or active projects, I tend to have them all open at once. Unfortunately, when I want, say, a web clipping, it is usually not the top focused library and pressing F1 sends the page into another library. Having to change EF focus adds an unnecessary step.
So the suggestion is that when F1 is pressed a list of open libraries comes up and asks where you would like to have the document stored.