Is it possible to manipulate the application symbol which are shown in the taskbar? Like operas symbol which doesnt look that well. In the kickoff i've chose a nice symbol for it, however when the application starts only the old symbol is shown.
Here is a screenshot if you don't understand what i mean.

http://img142.imageshack.us/img142/2461/57527809ag7.jpg

These images are set by the application themselves. Most applications load them from files, so if you replace the appropriate file, then you can do this.

Otherwise, this is not possible ( and probably never will because it would break the fd.o standard )

That's too bad but thanks for the information.

Some applications accept the 'icon=/path/to/icon' parameter at the commandline.