Version: (using KDE 4.1.3) OS: Linux Installed from: Gentoo Packages This is about the systemsettings module for the login manager (kdm): When "Use themed greeter" is selected in the "General" tab you only get the message "The background cannot be configured separately in themed mode." when you switch to the "Background" tab. This does not make sense, as the background can indeed be configured separately in themed mode and there is a need for the user to do so: The background image is visible for a few moments before the login screen and thus the background set by the theme is displayed. It is visible again for a few moments after you confirm your login, until the KDE splash is displayed. It is also visible if you start a session like "failsafe" where no new wallpaper is set. So the user may want to change the Background setting even in themed mode. Currently, you can easily do so by editing <kde4-root>/share/config/kdm/backgroundrc by hand, so why should the systemsettings module refuse to assist you with this? Disabling the "Background" tab when "Use themed greeter" is enabled therefore limits functionality in an undesired way and puts unnecessary obstacles in the user's way. Possible solution: Simply remove the check whether "Use themed greeter" is enabled or not. Alternatively, an informational message could be displayed at the top of the "Background" tab when "Use themed greeter" is enabled, but it should stay enabled nonetheless.
In addition to this, there's no real reason why the user shouldn't be able to select a background, even in themed mode, instead of the theme's background. Currently in order to change my KDM background I'm hacking up the theme to point to the image I want, but this is rather less than ideal. Having to make an entire new theme to change the background seems like overkill to me :-).
the background is by definition part of the theme. when you change it, you have created a derived theme. so i won't make it configurable. not all themes make changing it that simple anyway. the "normal" background being used with the themer would be a bug - the background extracted from the theme should be used in all the "corner" cases you mentioned above. even secondary screens should be covered nowadays.
closing, as there was no attempt to refute my irrefutable arguments in comment #2. :)