Notification Applet Not Keeping Old Notifications

[JSeiters]

Hello,
I am a new user to Kubuntu but have previously used OpenSUSE with KDE Plasma. I noticed that the notification applet in the system tray always stays hidden even when I am copying a file. And, as soon as a notification disappears it is removed from the applet. I have looked for settings that might be affecting this behavior, but I cannot find any. When I was using OpenSUSE the applet would keep track of all of the notifications and would unhide itself. Am I missing a setting somewhere?

Thanks.

[JSeiters]

It seems the problem was in my chair all along. I have version 5.10.5 of Plasma, not 5.11 and I forgot I was using OpenSUSE Tumbleweed, which, of course, is bleeding edge.