Version: (using KDE Devel) Installed from: Compiled sources I quickly scanned through the "Warning and Error Message" section of the KDE4 HIG draft on openusability.org, but I found no concrete information about the actual design of the labels inside of a dialog. The GNOME Human Interface Guidelines define such messages to have a (short) one-sentence, bigger and bold-faced "primary label", which contains the main theme of the dialog, and a smaller "secondary label", which has some more details to help the user make a decision. I always found this pretty practical and easy to scan visually. I think something similar might also be good to have in KDE's interface guidelines.