You can’t see that partition, because there’s no way to make it visible.
Apart from that, partitioning in El Capitan’s Disk Utility simply does NOT work.
Removing, resizing partitions will always result in a mess. It never does what one wants to do.
Off-topic:
Has anyone tried adding a new partition to a disk that has a desired size which you type into the size-field?
Has anyone tried doing so by adding TWO new partitions to a disk, specifying their exact sizes?
That stupid pie chart will always open up addidional slices that were never meant to be created.
Many times it will not even do its job, returning only error messages, and my iMac’s 3 TB Fusion Drive is shown as two Macintosh HD partitions of each 2,8 TB
and one Windows partition of 313 GB. Why??? There’s no TWO 2,8 TB HFS partitions. How’s that even possible on a 3 TB Fusion Drive?
Back to the original topic: Furthermore, you can’t do what this article tells you if Windows creates a hidden Recovery Partition that later on the Boot Camp Assistant doesn’t like. You’re STUCK. Unless you have the option to either use the Yosemite Disk Utility OR are a master of the command line.