The problem is that matlab wants a controlling terminal to be launched, unless you give the option -desktop. The correct way is to create a launcher that executes the following command
Code:
setsid matlab -desktop
The setsid command ensures that Control-C interrupts are correctly handled by matlab. In the KDE toolbar I created a new launcher and given setsid as executable and "matlab -desktop" as command line arguments. Specify the full path of the matlab executable if it is not in your PATH environment variable, e.g. "/matlab7/bin/matlab -desktop".