Yes. Other programs such as Glipper and Dropbox show their icons on every display while Radio Tray's icon is only visible on the primary one. It's clearly not a bug, that's why I set "enhancement" as the type of this issue. I'm not sure if being displayed on every monitor is the intended behaviour, I just thought I'm gonna let you know.
I have a similar issue. I have my primary monitor as the left one and when using Gnome Shell, the tray isn't so well supported (by Gnome) so it's hard to hit the corner without flying past it. What I would like to do is to add a hot key to pop up the radiotray menu. I'm a pythonist and I've been looking at the code, but it appears to me (too long away from GTK) that the action of displaying the menu is triggered by the tray, such that there isn't a method in radiotray where I could call it from the Gnome Media Keys (or similar) plugin. Ideas?