Version: (using KDE KDE 3.4.2) Installed from: Gentoo Packages It'd be nice if kmail folders could be set to be cumulative. What I mean by cumulative is that the parent folder would include all messages placed in that folder as well as all messages in the subfolders inside it. This way one wouldn't always have search through all folders to find a particular message, but simply look into the main category that that message should be in. At the same time this approach would allow for fairly fine-grained categorization. Along the same vein: A message should be able to reside in several different folders/categories, but still act as one message. Some other e-mail clients incorporate the concept to categories to create something like this, but AFAIK no mail client combines categories and the folder view into one consistent piece of functionality.
Sounds like a virtual folder to me. Have you tried to search for messages? This creates a virtual folder which you can even save so I this could be what you're looking for.
Yes, I know about the search folders, but they have the following problems (at least in kmail-1.8.2): - They can't be nested (meaning that subcategorization doesn't really work the way it should) - You can't drag&drop between them (ideally when you drop a message into a category, the message inherits the characteristics of that category)
Bug #116998 essentially describes the same idea and has more votes, so I'll close this bug.