UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36

Steps to reproduce the problem:
1. Start an XFCE desktop session.
2. Enable the composite manager (Settings -> Window Manager Tweaks)
3. Open a terminal and do an `ls -la` or `cat` some long text file, or do anything else you can think of to generate far more content than will fill the terminal.
4. Position your mouse pointer over the terminal.
5. Hold down ALT and roll your mouse wheel.  XFCE will zoom the screen in and out as per its screen magnifier feature, while the terminal will do nothing at all (this is the correct behavior).
6. Open Chrome or Chromium and go to any website with lots of scrollable content, such as a page of Google search results, or Facebook, Slashdot, etc.
7. Position the mouse pointer over the browser page content.
8. Hold ALT and roll the mouse wheel.  The web browser will scroll the page up and down at the same time as XFCE zooms the screen in and out.

Please understand that I am NOT referring to Control-wheel, which would change the local page zoom.  I am talking about ALT-wheel, which zooms the whole screen and everything displayed thereon, via XFCE's composite manager.

What is the expected behavior?
Like the example with the terminal in step 5, Chrome should do nothing at all while ALT-mouse-wheel is being used.

What went wrong?
The browser will scroll the page content up and down while XFCE's screen magnifier zooms in and out.

Did this work before? Yes Not sure, at least a year ago.

Chrome version: 59.0.3071.115  Channel: stable
OS Version: Debian 9 "Stretch"
Flash Version: 

This problem does not occur with any application other than Chrome and Chromium.  For example, Firefox behaves as expected, as do my terminals, Hexchat, Claws-Mail, etc.

This has been broken for over a year now (I just never bothered to write about it), except that there was one brief period not too long ago where Chrome worked fine, then it broke again.

If desired, I can take a short video recording (with a separate camera, rather than a desktop recorder), demonstrating the effect.