It took me about 3 hours of debugging and searching in google until I
found out, that the small line at the bottom of Eclipse is called
"StatusBar". After that it was much easier to search for information
about that line.
I found the class org.eclipse.gmf.runtime.common.ui.util.StatusLineUtil.
With that class it`s very easy to set an ErrorMessage in the StatusBar.
In the Properties-View there`s only one thing where you should pay
attention: Don`t take the IWorkbenchpart that comes with the method
setInput() when you call StatusLineUtil.outputErrorMessage().
You have to get the part like this:
IWorkbenchPart part =
PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getActivePart();