User altered a DMS tablespace | selected Advance Resize | Edited Size | executed successful. When coming back on Space Management, Calculate Space. Toad did not show the change even refreshing all. However, Quest Central for DB2 was showing correctly the change.
Waiting for a fix with CR/ST 70,187 on a future release of Toad for DB2.
After altering the tablespace, user can do a refresh all and opens Calculate Space to get the right values.