When I clicked on the update icon in the system tray area, it didn't invoke the update.
It had worked successfully earlier the same day.
I checked, and more updates were available (for mga7).
Using a minor clic on the update icon, some other things didn't seem to work, so I clicked on the exit option (quitter in french).
This removed the icon, as expected.
I then logged off/on, the icon did not reappear.
I then rebooted, once logged on, the icon did not reappear.
I tried going directly into rpmdrake and selecting show all updates, selecting and updating a few but not all.
Still after trying loggoff/logon and reboot, the update icon in the system try is not displayed.
How to recover the update icon ?
Problem caused by updates-testing activated in rpmdrake.
Once deactivated, rpmdrake shows no updates available when mgaapplet is not displayed.
The initial problème (constantly displaying update icon) was a temporary glitch.