Version: (using KDE 4.3.2) OS: Linux Installed from: Ubuntu Packages As I said: If you change a directory icon (for example, select folder-yellow) and you have such directory filled with images or other pre-viewable content, Dolphin produces these nice previews on top of the folder. However, it uses the default folder (the light-blue one) to produce the composition, instead of the yellow one you selected for that particular folder.
Thanks for the report. This issue is known already. *** This bug has been marked as a duplicate of bug 201850 ***