View / edit control points in Impress and Draw

Hello,

In the release notes for LibreOffice 5.1
https://wiki.documentfoundation.org/ReleaseNotes/5.1 it is mentioned that the
control points can be adjusted manually by inserting the X and Y values. Right
clicking on the figure and choosing Position and size opens the dialog but it
does not work for me as these spinboxes are greyed out. Am I doing something
wrong or is it a bug? I am working under Windows 7 with LibreOffice 5.1.2.2

Many thanks
Best regards

Leo Moons
LibreOffice/nl