[Pharo-dev] AthensCairoSurface not getting garbage collected

I'm using Athens rendering for my multi-touch applications on Pharo5. As part of that, I create a surface: surface := AthensCairoSurface extent: bounds extent asIntegerPoint. Though the object creating that surface is deleted, the surface sticks around. So, each time I run the app, I get another instance of AthensCairoSurface hanging around. That means all the forms stick around as well. So my image can quickly grow towards the 1GB size. Is there anything I can do about that? Can I manually get the surface to delete itself? Cheers, Jeff