Should not scroll on Alt+Click

Alt+Click on the big handlebar of overlay scrollbar.

Expected result: Nothing should happen, apart from bringing the window to the foreground and preferably even grabbing it for move. The contents inside the window should be left intact.

Actual result: It scrolls the content, just as if I clicked on the scrollbar without Alt.

Rationale:

Alt+Click is commonly bound on all kinds of Linux desktops/WMs to raise and move the given window.

If it has any side effect, e.g. mangles the content (even if it just scrolls away from the desired location), I can no longer safely use this shortcut quickly and efficiently.

It should not have any other side effect, e.g. Alt+Click on an X button (either the WM decoration's close button, or a close button on a Gtk+ tab) or any other UI element doesn't perform that element's action either. This behavior has been the standard on pretty much every desktop environment I've seen under Linux for the last almost 20 years since I've using it (beginning with fvwm, but as far as I recall, even twm behaves this way).

The correct behavior of Alt+Click would be to bring the window to the foreground in the exact same state it was when it was lowered or covered by another window, and not to alter the application's state in any way, not even when I happen to Alt+Click over the overlay scrollbar.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: overlay-scrollbar 0.2.16+r359+15.04.20150319-0ubuntu1
ProcVersionSignature: Ubuntu 3.19.0-15.15-generic 3.19.3
Uname: Linux 3.19.0-15-generic x86_64
ApportVersion: 2.17.2-0ubuntu1
Architecture: amd64
CurrentDesktop: Unity
Date: Tue May 5 21:34:29 2015
InstallationDate: Installed on 2012-05-30 (1070 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
PackageArchitecture: all
SourcePackage: overlay-scrollbar
UpgradeStatus: Upgraded to vivid on 2015-03-17 (49 days ago)