I have a problem with the panel in plasma-netbook since KDE SC 4.4.2. The panel disappears with a little "slide-effect", when I open a program like dolphin or rekonq. It reappears, when the "systemmessage thing" (the notifier in systray, dunno what its name is) says something. The problem is, that plasma-netbook is unusable for me, if the panel disappears. I cannot close or maximize/minimize programs, I don't see the time, the systray and cannot switch between the search&launch and newspaper activity.

My question is: Is this a bug or a feature and if this is a feature, how can I stop the panel from disappearing?

Make sure the Panel Visibility setting is set to "Always Visible". It can be found by right clicking on the Panel > Panel Options > Panel Settings > More Settings.

I don't know what you mean. There is no such thing as "Panel Options > Panel Settings > More Settings".

There's only a "Panel Options for Netbooks" (in german, that is. But this should be the right translation) and the only option I have is to add more plasmoids. If I click on this kidney in the lower left, I get the option to enable "automatically fade out" (or what the correct translation is), but with this, it fades out, but fades in, if with the mouse pointer is in the upper screen, or so.

The option is disabled here, but the panel still fades out. So I guess, this is a bug?

If the fade out option is disabled and the panel fades out, then that is a bug, please file a report at bugs.kde.org.

Bugreport: bug 234149