In addition to the "Keep above option" on windows, I think it would be nice to have an option to automatically resurface the window after any window covering it loses focus. It would be especially handy for multi-screen setups where you have a display where you generally want something like a process monitor like "top" on top, but then use another application that will temporarily cover the process monitor window now and then. When you continue work on your other display, the process monitor window would reappear.
I think this is quite specific workflow. In general, for such things you would need to use a script. If we don't expose enough API to implement such a thing, please file another bug report against scripting component.