Thanks for the heads up on loosing that sidebar junk.
ok, found out how to REMOVE the sidebar, and return the wasted space (ie: wide posts).
Edit your Details
scroll down to Additional Information
Toggle right Sidebar and select Disable
then go to the very bottom and select Save Changes
(Thanks! to whoever posted this, this morning)
for the record, if all of the long-time members are asking how to return it to how it used to look, maybe it shouldn't have changed! And maybe it should be the DEFAULT, not something you have to hunt thru and re-configure!