OH MY GOD YES: A hack to fix keyboard-based list multi-selection in Cocoa apps to not do that horrible shift-cursor selection growth thing, you know the thing in Mac Mail where you select a message then hold shift and cursor down to select more messages, but you go one message too far so you cursor up, only to discover that what that does is select another message above the top of the list instead of shrinking your selection.

It doesn't work for everything. Finder, for example, retains this selection behavior. But it works in Mail.