Steps to reproduce:
1) Disable "Raise window when clicking inside application window" in Window Manager settings in Xfce (in Focus tab).
2) Move another window to partly overlap chromium browser window
3) Click on the chromium browser window below title bar
Actual result: the window raises
Expected result: window should not raise
This is only an issue if "use the system title bar and borders" is not set in Chromium settings
Tested with Ubuntu 18.04, Chromium 69 and xfwm 4.12.4-0ubuntu1
See also https://bugs.launchpad.net/bugs/1054923
Is that with "system title bars and borders" ?
Because if Chromium is set to use its own decorations, then xfwm4 has no idea what's the actual window content as opposed to the decorations that it doesn't draw... So that's normal.
Client side decorations and "click inside application" do not mix well.