It's very handy to send any open Ubuntu window to below all other open windows (it says open yet now occluded) by clicking mouse middle button on window title bar (opposite of left mouse click to bring to focus front) ... this fails on Ubuntu 17.10's new file explorer called Files 3.26.0 which has a non-standard looking title bar.
This behavior continues to be OK on all other 17.10 applications... Nautilus worked OK, but it looks like it's no longer the default file manager... I hope other apps refrain from using this new window behavior
I have nautilus installed and on launch it becomes Files 3.26.0 exhibiting this bad behavior... Nautilus works fine on Ubuntu 17.04 and earlier
Any ideas on why Files breaks this convention? Or how to fix it?