Icon in systray

I have the em client icon in the systray. In the beginning, when I get mail, the icon changed in a box figure and I see a popup. Later on the icon did not change anymore. Now, when the popup disappeared (after a minute or so) I cannot see from outside that I have new arrived emails. What can I do to change the icon when I get mail?


please check if you have this turned on in Tools - Settings - General - Notifications