New install - why no "install to largest empty disk space" option?

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http://www.kubuntuforums.net – So i finally did the dual boot install. took me a while to get soem money for external disk (backup). anyway the install is in BIOS netbook HP dm1. all works out of the box. sound crackles a bit in Skype. during the install preparation i got the following screen: http://ubuntuone.com/1CNu32SyCH6RlsLc7GFQBL i've created empty disk space to use for Kubuntu (i left larger portion of disk formated in NTFS as Kubuntu can save to NTFS if needed. my question is: why i didn't get any offer for install to largest empty disk space? And furthermore the manual partitioning in installer is n (HowTos)