[Dillo-dev] Crashes in dw::core::Layout::createImgbuf()

For the last few days I have been getting occasional crashes inside dw::core::Layout::createImgbuf() when opening a new tab. It does not seem to be predictable: if I restart Dillo and reopen all the URLs I was just looking at it is fine. The gdb backtrace often shows ridiculous values for this: eg. the attached example has this=0x6. I've seen other impossibly small values for this, but sometimes the value seems more sensible. Any ideas? I'd like to investigate further but I don't know what to look for. Pointers are welcome! Regards, Jeremy Henty