Actually there are no informations about the option "hide whitespace" (Swriter/.uno:HideWhitespace), although it is important to know that the option is not available, if you set the view layout to automatic. The problems are described in bug 98446.
From the 5.1 release notes:
"Hide Whitespace option added to View menu tdf#39080 (Ashod Nakashian, Collabora)"
This is now fixed with bug 132630.