Focus "mouse" or "sloppy" do the same thing on gnome-shell

Question

My problem is actually very annoying. I am very familiar with the mouse focus but right now it's not working.

Inside gnome-tweak-tool the last option "windows" has the "windows focus mode" switch. I've set it to "mouse" but it does not work. It acts just like the "sloppy" option. I hope another gnome user understands my issue.

UPDATE:

Answer 1

In a standard gnome-shell setup, mouse focus and sloppy focus behave identically. The reason is simple: there is no DESKTOP. The mouse focus method, particularly, needs a DESKTOP in order to work properly but there is no such thing in gnome-shell, in its standard incarnation. Unfortunately, this is only documented in mutter docs. dconf-editor still has the old key/values description from Gnome2 metacity times and gnome-tweak-tool doesn't even provide a description let alone toggle the DESKTOP on once you switch to mouse focus.
Here is an excerpt from mutter-3.**/doc/how-to-get-focus-right.txt:

Focus method  Behavior
    click     When a user clicks on a window, focus it
   sloppy     When an EnterNotify is received, focus the window
    mouse     Same as sloppy, but also defocus when mouse enters DESKTOP window

Note that these choices (along with the choice that clicking on a window raises it for the click focus method) introduces the following invariants for focus from mouse activity:

Focus method  Invariant
    click     The window on top is focused
   sloppy     If the mouse is in a window, then it is focused; if the mouse is not in a window, then the most recently used window is focused.
    mouse     If the mouse is in a non-DESKTOP window, then it is focused; otherwise, the designated "no_focus_window" is focused

However, there are a number of cases where the current focus window becomes invalid and another should be chosen.  Some examples are when a focused window is closed or minimized, or when the user changes workspaces.  In these cases, there needs to be a rule consistent with the above about the new window to choose.

Focus method  Behavior
    click     Focus the window on top
   sloppy     Focus the window containing the pointer if there is such a window, otherwise focus the most recently used window.
    mouse     Focus the non-DESKTOP window containing the pointer if there is one, otherwise focus the designated "no_focus_window".

Now, back to your problem. You have to "enable" the DESKTOP in order to have mouse focus working properly. This can be done:

• using gnome-tweak-tool > Desktop > Have file manager handle the desktop > ON
• using dconf-editor >> org.gnome.desktop.background >> show-desktop-icons > checked
• in terminal, running: gsettings set org.gnome.desktop.background show-desktop-icons true

Restart gnome-shell after applying all your settings.