Hello.
I use a couple of (non-KDE) applications which put their icons into the system tray. In the KDE 4 when I moved the mouse pointer to such icons a tooltip which was set by the application was appearing. In the KDE 5 this tooltips are hidden, but a non-informative ones which contain a name of the application and its icon is shown instead.
But in rare cases after a long work of the KDE 5 I watched a situation when a native tooltips "bursted" through the KDE framework, as shown at the screenshot:

I have a simple question: may I return an old behaviour of the system tray? I really need to see an information which an applications put into its tooltips.