This data narrows it down some
I went here before buying to see if this is being looked into, because I keep getting it. I tested 5 machines, all Chrome & Windows instances up to date.
No Good (left half on first Shadowbox opening):
Dell Inspiron Laptop, Vista Home Premium, AMD Turion 64, 32 bit OS, 2 GB Ram - NG
MSI K8T Neo 2 Homebuilt, Win XP Home, AMD Athlon 64 3500+, 2.2 GHz, 2GB Ram - NG
MSI Wind, Win XP, Intel Atom N270, 1.6 GHz, 2 GB Ram - OK!
Dell Studio XPS 435MT, Vista 64, Intel Core i7 920, 2.67 GHz, 6GB Ram - OK!
Dell Optiplex GX270, Win XP Pro 32, Pentium 4, 3 GHz, 1GB Ram - OK!
Looks like an AMD vs. Shadowbox vs. Chrome issue.
Hope this helps get it fixed.