I have a plug-in with a view that contains an image. Now I want to create another plug-in, which catches click events in the first plug-in and draws an overlay circle on it. I could successfully export the canvas with the image and access it in the other plug-in, and even catch the click events in the other plug-in. Unfortunately, I could not paint on the canvas (with addPaintListener() and update()). First I got an exception, because it was not in the UI thread. When I do the drawing stuff wrapped by Display.getDefault().asyncExec(...) the asynchronous part is never started Can anyone help me please?