Fullscreen to hide i3bar and border only
Fullscreen mode of some applications with i3wm is the same as application's internal fullscrenn mode, for example, in Firefox, what I get with F11 and Mod+f are the same, but what I expect when pressing Mod+f is just maximizing current window and hiding i3bar and border, without hiding any firefox component. Is it possible to make i3wm's fullscreen mode behaving like this?
At first I was puzzled by this as well. Meanwhile I got used to it and find it ok/logic. Getting some more background info on this would be nice.
try mod+a (focus parent) then mod+f, or for firefox you can disable interface autohiding in about:config parameter "browser.fullscreen.autohide"
This might be a Firefox bug. Using Chrome - F11 goes full screen and hides the URL and tab bar etc. Whereas, mod+f maximises Chrome keeping the UI intact.