A few applications on my Plasma desktop (in particular Zim and the client for my VPN) have icons in the system tray. Is there a way to assign a keyboard shortcut that would open those items so that I don't have to click on the icons? I can set shortcuts for ordinary Plasma widgets by right-clicking on the icon and going to Configure > Keyboard Shortcut. But for standalone applications that were not meant to be specifically Plasma widgets, such an option does not exist.

The only thing I can think of doing is to create a shortcut to launch the application itself. This is not a solution, because it would just be re-launching an already-launched application (in the case of Zim it actually launches a new instance).