This is a big bug that's a bit harder to explain and it has many side effects:
1. Create a couple of tables as the "dba" user. Create an user named let's say "testing" with any password. Then leave the select checkboxes as they are. Then log out and login as that user. No tables will be displayed.
I checked in cubrid manager the privileges for the user and select options were unchecked. I then checked the checkboxes (gave the user select rights on both tables) using cubrid manager (the insert privilege worked fine though...only select had an issue so far)
Then, when I went to the edit privileges page for the user I just clicked "go" (with select boxes checked by default) and it returned "Success", but this led to problem 2.
2. If the user had select privilege then clicking "Go" removes the privilege. I checked in CUBRID Manager the rights and they looked like in the cubrid_manager.png image.
Please tell me if there is anything unclear with my explanation. The "SELECT" right works incorrectly in almost all circumstances. For example, another problem was unchecking the select boxes and then clicking go. Immediately they got checked again after it said "Success".