Pop up window action menu when right-clicking a window in the windowlist menu

It would be handy in the window action menu could be accessed from the window list one gets by middle-clicking the desktop, by right-clicking the item on the list --- this is the behaviour of the window list accessed through the windowlist panel plugin.

In general, it might be best if window lists would exhibit uniform behaviour, regardless of how they are accessed. For example, both the desktop window list and the windowlist plugin window list could respect the user's choice (from the window buttons config) of what to do on middle-click (nothing, close, minimize).