Description:
Writer: Vertical (side) ruler not adjusting to page with 'Hide Whitespace' view, Easily visible when toggling view (WhiteSpace Hide/Unhide)

Steps to Reproduce:
1.Open Writer
2.use vertical (side) ruler (from dropdown menu 'View')
3.Toggle 'Hide Whitespace' - 
4.Vertical ruler is not correlated to the changing view/page position

Actual Results:
Whitespace at page top hides as expected; 
Vertical ruler does not change when Hide Whitespace view:
 - its 'header' location correlates correctly with 'normal' view - and changing it will change the page head/ text position - but Ruler does not correlate in 'Hide Whitespace' view

Expected Results:
Vertical ruler should 'hide' its 'header' portion (gray section at top of ruler) to correlate with changing page view/ visible pagelength on screen


Reproducible: Always


User Profile Reset: No



Additional Info:
100% every time reproduceable, including after closing/reopening whole LibreOffice or Writer pages.