Focus changes to xfdesktop when switching into a workspace with a fullscreen window

I noticed this after upgrading to Xfce 4.18. As mentioned in the title, if the focus of the target workspace is on a non-gtk fullscreen window, the focus changes to xfdesktop (I monitored it by using watch xdotool getactivewindow). But it also depends on the way of switching workspaces and the context.

Here is some situations where this bug doesn't happen:

• If you switch the workspace by using the pager panel plugin.
• If the current focus is already on xfdesktop. So when switching workspaces, the focus changes as expected.
• If the current focus is already on a fullscreen window.
• If the target workspace is already focused on xfdesktop, so the focus changes automatically to the fullscreen window.

To exemplify the last situation, let's say that you have 2 workspaces: the first is focused on Mousepad (that is not at fullscreen) and the second is focused on Krita (that is at fullscreen). When you switch from the first workspace to the second, the focus changes to xfdesktop. So when you switch back to the first workspace and switch again to the second (where the focus is on xfdesktop), the focus changes back to Krita.

I didn't find anyone reporting this on Manjaro Forum, so maybe this bug is caused by some configuration that I've changed before. But since I don't remember changing such a configuration, I decided to open this issue.

Edit: As I commented below, there is a new addition to what I described above. Even though the behaviour described still happens, there is a case where the focus acts as expected that I describe in the comment: #697 (comment 81601)

Xfwm4 version: 4.18.0 | OS: Manjaro Linux with Stable repository