Graphviz preview make window bigger than screen

I really enjoy the addition of graphviz diagrams in Zim. An excellent way to add quick flow illustrations and to keep graphviz files organized.

I do have a problem, though: If the graph get big, the preview window will become bigger than my screen and I cannot push the OK button to save. If I add a size= command in the input text and press preview again, the graph get smaller, but the window stay the same size. I have found no other way than to close the window with the "X" in the window manager and lose work.

In all new graphs I use size= to limit the size of the resulting graph, which will keep the preview window within the size of my desktop, but the first couple of times it was frustrating to lose work as soon as the graph got too big. I don't know if this is something already known so I ask before claiming it to be a bug. New features are seldom ripe the first time they are introduced. I use Debian with zim installed from the debian repository (currently 0.28) and prerequisites defined by the debian packager.