I think its not a problem with "tray icons" specifically. Somehow CIS 4 breaks "compatibility mode" for any windows executable. So WLM tray icon mode, that uses Vista or XP comp mode, is broken.
I run several old programs in compatibility mode and after CIS 4 installation, they doesn't work any more. For example, I have to install my Creative webcam drivers in vista sp2 comp mode. With CIS 4 installed comp mode, they refuse to install. Also for HD Tach HDD benchmarking software, it has to be run in XP comp mode. Also it doesn't work.
Defense+ is totally disabled (and sandboxing too), and it doesn't seem to make a difference. BTW, can CIS 4 be installed WITHOUT Defense+ or sandbox to see if that is the problem? We used to have that option in CIS 3.x, but now it can't be done. To get rid of Defense+ it has to be disabled after that.
So it's nothing to do with tray icons, but windows compatibility mode in links itself.
Please fix this bug, because we all love CIS but this issue is very important to leave it behind.
Windows 7 64-bit here.
As is described in this post
(reply 9), if Defense+ is disabled permanently, compatibility mode is working again.