I cannot delete records using 220.127.116.114. I could with the last beta and 5. :(
By default grids are read only. To toggle the grid to be editable click the red icon in the lower left of the grid. You can also change this default back to the previous one in Tools|Options|Environment|Grid and the option is called "Show data as read-only" (Lower right).
Your answer resolves this -- just odd that it reset with this beta, not others.
Nothing mystical about it :). We changed the default for this option so unless you have changed it you got the new default.