Using SQL Developer version 4.0.2.15, I'm noticing the describe command exhibiting some odd behavior.
When I try to execute the following statements:

I get the following results:
SYS_CONTEXT('USERENV','SESSION_USER')
------------------------------------------------------------------------
SWALTERS
session SET altered.
table PS_ACAD_SWALTERS created.
DESC SYSADM.PS_CU_BDG_ITEM_TBL
ERROR:
-----------------------------------------------
ERROR: object PS_CU_BDG_ITEM_TBL does not exist
DESC SYSADM.PSOPRDEFN
Name Null Type
----------------- -------- ------------
OPRID NOT NULL VARCHAR2(30)
VERSION NOT NULL NUMBER(38)
.... snipped ....
LASTUPDOPRID NOT NULL VARCHAR2(30)
PTALLOWSWITCHUSER NOT NULL NUMBER(38)
DESC SYSADM.PS_ACAD_PROG
ERROR:
-----------------------------------------
ERROR: object PS_ACAD_PROG does not exist
desc PS_ACAD_SWALTERS
Name Null Type
------------------ -------- ------------
OPRID NOT NULL VARCHAR2(30)
VERSION NOT NULL NUMBER(38)
.... snipped ....
LASTUPDOPRID NOT NULL VARCHAR2(30)
PTALLOWSWITCHUSER NOT NULL NUMBER(38)
So, from this example we see that I created a test table from an existing table, and was able to successfully describe it, but I'm not able to jump across schemas to describe the original table. That's odd.

If I jump to the original schema, I get the following results:
SYS_CONTEXT('USERENV','SESSION_USER')
-------------------------------------------------------------------
SWALTERS
session SET altered.
DESC SYSADM.PS_CU_BDG_ITEM_TBL
ERROR:
-----------------------------------------------
ERROR: object PS_CU_BDG_ITEM_TBL does not exist
DESC SYSADM.PSOPRDEFN
Name Null Type
----------------- -------- ------------
OPRID NOT NULL VARCHAR2(30)
VERSION NOT NULL NUMBER(38)
.... snipped ....
LASTUPDOPRID NOT NULL VARCHAR2(30)
PTALLOWSWITCHUSER NOT NULL NUMBER(38)
DESC SYSADM.PS_ACAD_PROG
ERROR:
-----------------------------------------
ERROR: object PS_ACAD_PROG does not exist
DESC SWALTERS.PS_ACAD_SWALTERS
Name Null Type
------------------ -------- ------------
OPRID NOT NULL VARCHAR2(30)
VERSION NOT NULL NUMBER(38)
.... snipped ....
LASTUPDOPRID NOT NULL VARCHAR2(30)
PTALLOWSWITCHUSER NOT NULL NUMBER(38)
DESC PS_CU_BDG_ITEM_TBL
ERROR:
-----------------------------------------------
ERROR: object PS_CU_BDG_ITEM_TBL does not exist
DESC PSOPRDEFN
ERROR:
-----------------------------
ERROR: object does not exist
DESC PS_ACAD_PROG
ERROR:
-----------------------------------------
ERROR: object PS_ACAD_PROG does not exist
If I use SQLPlus, I can describe all these tables successfully. The SWALTERS user currently has SELECT ANY TABLE and RESOURCE privileges granted to it.
Is this another quirk of SQL Developer, or something complete different. All suggestions appreciated.