Trying to Remove Block

I'm trying to remove the block under Builders > Navigation Menu Builder > Orca (Forums), and I'm trying to remove Search, My Flags and My Topics. When I click on the block it doesn't let me edit or change anything, it's read only. How do I remove these blocks?

You should be able to just drag these items to the bottom part of the window.  Use firefox to do this (it works best for dealing with admin panel)