I just want to report a little bug on the tree component.
As you can see on this picture, the root tree expanded image doesn't have a transparent background whereas contracted image and contracted and expanded image nodes [+] and [-] are ok.
this is a known issue. I've seen that you already created a JIRA for this.
Yet, there exists another JIRA describing the same problem: ICE-1414
It might be possible that there are some more images without transparent
backgrounds, so it might be reasonable to check all images for correct
background layers.