Cloud view: Loading (instances, images) freezes the UI

how to reproduce:

1) make sure you have at least 2 clouds: one with a lot of images (or instances), another one with a few images
2) make sure you have image view opened (or instance view, if you have a lot of instances on a cloud)
3) make sure to select the cloud with the few images in the image view (or do the same with instance view)
4) restart deltacloud client (eclipse)
5) go to cloud view and select the image tree-node in the cloud with many images

Result:
UI freezes while data is being loaded from the server

Expected result:
UI does not freeze, Operation is shown with a progress-bar