Missing icons in the message tray on Fedora 21

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Some of my applications, such as Insync and Viber, appear in the bottom message tray when running, but without any icons. I can control them using left/rigth clicks, but without status icons I cannot quickly inspect if my files are sync'd or if there are any new messages.

Is there any way to restore the missing status icons?

Update 1

I solved the issue with Insync by uninstalling insync-nautilus extension.