Sid1996, thanks for the detail report.
Well, now both craigb and sid1996 are saying the same, and it happens to be the same as Vlk said: the problem with gadgets happens only when checking for available program updates.
Using the default settings (program update -> ask), this problem occurs once in a while, when a new program update is attempted. Since the user is supposed to reboot after the program update is performed and finished, and since the problem doesn't persist after a reboot, the problem occurs only once in a while with no permanent serious consequences.
In addition, Avast main GUI displays the relevant info when a program update is available, even before displaying the program update tray notification. This means that there is no need to keep trying if there is a program update available, except when you already know there is.
Still, I hope Avast Team can find a way to solve this problem.