how do you remove a profile?

When I chose "project settings" there is a video profile drop down - there is one which I would like to remove as it is so non-standard and I somehow accidentily must have selected it one time and the rendered files would not play back on my TV
the profile is
768x576 4:3 PAL
a more standared setting for pal dvd is
In the video tutorial here
it says you can remove a profile by going to
Settings/manage project profiles
and then choosing the profile in the drop down and then clicking the bin icon which will be red colour
well the bin icon is grayed out when I try that so I cant get rid of this profile.