Setting backgroud image results in duplicate style rules

Hi @artf,

I have one strange little problem. I have a custom trait which has an implementation for setting images and background images. When I set the background image a second time by using the code below I'm getting duplicated styling rules on the element Id.

var style = self.target.getStyle();
// style is empty even though the stylemanager shows the default background image from the class style rule
style['background-image'] ='url("' + newUrl + '")';
self.target.setStyle(style);

I already played around a bit with the forceClass and avoidInlineStyle but it doesn't really help with this problem. Maybe related to this problem: The element also has a class with a default background image. When I open the StyleManager I only see that background image in there. Not the images from the Id style rules. Looks like it doesn't really use them at all?

Thanks in advance!