Problem with multiple monitors and workspaces

Maybe you have an idea how to fix a problem I have.

I have 2 monitors.

When hitting windows/super key I see all open windows on current workspace.

This works well for the right hand monitor.

However, on the left hand monitor I see all open windows independent of the workspace.

Do you have any idea what this might be?

I would like to have an isolated workspace, when hitting the win key to show only the open applications in this current workspace.

I tested already the following command:

$ gsettings set org.gnome.shell.extensions.dash-to-dock isolate-workspaces true

It didn't work.

To be clear, I'm talking about the Activities overview which shows all open windows in current workspace.

Windows on right monitor are only shown in the overview when I'm on this workspace. However, on left monitor all windows are shown every time.

Here is an example of my screens Hitting super key

As you can see, on current worksapce I only have gedit open on right screen. However if I hit super key, it also shows firefox which is open on a different workspace on left screen. But I only want to see open applications on current workspace, which is just gedit in this case.

Solution: Follow instruction found here: https://askubuntu.com/a/1125322/169671

I'm not sure what you meant on I see all open windows independent of the workspace. Do you mean you see all windows in the system, or all windows in the left screen only? So, in the end, do you mean you want to hit Super key, and only open overview on one screen only, or to show on both screen as usual, but only show what's on that independent screen only?

If it's the first case, I don't think that can be done easily. But if you just want separate overview for each screen, it's quite simple. If you have GNOME Tweaks installed, open it, go to Workspaces. Under Display Handling, select Workspaces on primary display only. Otherwise, you can just run
gsettings set org.gnome.mutter workspaces-only-on-primary true
gsettings set org.gnome.shell.overrides workspaces-only-on-primary true

If you need the reversed, set to the other option in GNOME Tweaks, or run
gsettings set org.gnome.mutter workspaces-only-on-primary false
gsettings set org.gnome.shell.overrides workspaces-only-on-primary false
After that, check out this answer at https://askubuntu.com/a/1125322/1476180 to make overview work properly