Much as I love KDE, I've never figured out what half of the Kwin special window settings do, much less the difference between special window settings and special application settings. All I want to do generally is have most apps that I run frequently remember their size and positions. But what I generally end up with is a few apps working right and others having all of their windows conform to the remembered settings. For example, Firefox. Regardless (I think) of whether I make the remember size and position settings window or application-specific, it seems any firefox popup windows open the same size as my main firefox window. This applies to dialogs that websites put up as well (I think) as dialogs Firefox itself displays.
My best guess is that Application settings apply to a class of window (as defined by the app when it creates the window) and Window settings are somehow tied to the titlebar text. Neither seems to be appropriate for remembering the main window geometry and having dialogs center over the main window (or do whatever they would do without any special settings).
Is this just a remnant of missing functionality in the underlying X-Window system? Are X-Windows not identified uniquely enough at creation for kwin to find them across application invocations? If so, I think it would be better to have apps do the remembering than kwin, since kwin doesn't seem to do it all that well.
Is this a common complaint, or am I just cranky? It seems to me that a global 'remember size and position for everything' (that actually works reliably) would be better than all the 'special window settings' combined...