"endless" eventLoop when creating new Instance

Hi everyone,

I'm pretty new to Eclipse-Plugins and I have a major problem.

I've created a simple menu-entry with a handler. In this handler I create a new instance of a certain class of a referenced package.

Well, it does not work and the code after the instantiation is not even executed (I have tested it by simply adding a message-call after it).
When I debug the plug in the EventTable.event is called and it results in a "endless" eventLoop in the IWorkspace class.
I do not understand how EventTable is connected with the creation of the new instance.

I have once had a similar problem when I created an instance of a class of another referenced package. Weirdly enough, I was able to solve this problem by replacing my implementation of a conventional popup-action with the command/handler pattern.

I know my description is not very precise, but I hope I can give you more details afterwards.

Any help is appreciated!