When we have multiple windows for an application, implement the following
behavior:
* On click + immediate release, go to the most recently used
* On click, hold for 0.6s, pop up a menu with windows, filtering
the window list to just those windows.
Mouse over on the window list highlights the moused-over window.
Implement this by splitting well item into InactiveWellItem
and RunningWellItem, sharing a base class BaseWellItem.
