I'm not able to switch to Seamless Mode in VirtualBox with Ubuntu 10.04 or 9.10 as guest OS's. I have tried the seamless mode with XP as guest OS, and it works absolutely fine. The host OS is Windows 7.
I have in-built Via/S3G Unichrome Pro IGP graphics, and I have allocated 30 MB out of 64 MB of graphics memory. I've also 1.5 GB of RAM.
I also tried installing Guest Additions but it still didn't work. VirtualBox version is 4.0.4r70112. The Host+L does not lead to seamless mode. i.e. under the Machine menu in Virtual box window "Seamless mode" is disabled (comes in grey color). How can I get the seamless mode to work? Please help!