Running Mint 12 KDE. I have Evolution and Weather Indicator (indicator-weather package) installed. Some of the icons in both of these applications are missing. Perhaps they rely on something from Gnome or a gtk resource that did not get loaded? Any ideas?

If you open the menu editor (right click on the menu icon in the panel) and locate the applications, are they still missing their icons there?

Also, what type of icon is being displayed instead? Is it a question mark icon?

No, the application icons are OK. The problem is the icons WITHIN the application. For example, some of the icons for the buttons. In Ubuntu, the button icons did not seem to be application specific, but rather would change with the system icon theme. Of course, that was under Unity (using Gnome's icon themes). Since I'm running KDE without Gnome, perhaps it is looking for a handle to Gnome icons?

Yes, this is likely because GNOME does not follow freedesktop.org icon naming conventions, and instead uses their own (whilst KDE follows freedesktop.org conventions). Unfortunately, unless there is a way to specify that GNOME/Gtk applications look at a different, GNOME, icon theme instead this will be difficult to solve.

This is probably possible through a ~/.gtkrc-2.0 configuration option.

Well, I've replaced the weather app with a better-behaved one (with more features, and prettier! - I love KDE!), so that's not an issue. It's just the e-mail app, and I'm quickly growing tired of that, so I may start exploring alternatives. Thanks anyway!