Indeed. I tried to implement a fast project switcher plugin at one point; ie., a plugin to quickly switch to another window by autocompleting its project name,

Indeed. I tried to implement a fast project switcher plugin at one point; ie., a plugin to quickly switch to another window by autocompleting its project name, like super+P (instead of having to cycle windows or use the window menu, both of which are poor UIs when you have anything more than two windows open). But the API doesn't support focusing windows. You can switch focus to a different buffer in an arbitrary window, but it won't make the window itself active. I reported the limitation in the forums. Never got a response. Didn't surprise me; I have reported a bunch of other problems, hardly any of which received Jon Skinner's attention.