memory leaks while drawing images

Hello. Please, can anybody tell me the correct way to display an image on an application pane? I tried the approach written in the "image-viewer" example, but when I run that example, the program leaks memory. Every time that the function draw-pattern* was called the memory reported by (room) increased and eventually SBCL runs out of memory so the game is over. I create the pattern with make-pattern-from-bitmap-file and then I display it with draw-pattern*. The code that shows up the problem is attached. I also include res.txt which collect the output of     (progn (sb-ext:gc :full t) (room)) that I evaluated after each execution of the command that displayed the image. Thanks in advance for any suggestion.