Why on earth do you have columns which begin with a "."? Of all the bizarre naming conventions I've come across that is the most bizarre.
Given that "." is the separator for name components, I suspect the identifier quoting mechanism in SQL Developer is being fooled and isn't able to generate its query string properly.
Hah, I know, but it wasn't my call and there's nothing I can do about it.
EDIT: The thing is, I have a colleague who says he can see the columns, but he is in another office so we can't sit side-by-side and compare.
You CAN do things that MIGHT screw stuff up in the product. I blame the ANSI folks, but it's our bug. I can reproduce this, will log it.
I am trying to view a table that has some column names beginning with a dot, ".".
Did it occur to you to actually TELL people what database and version you are even talking about?
When you post questions you need to provide enough information so someone can try to reproduce the problem.
It is possible your colleague is using SQL Developer 1.5.5 or earlier. I did a quick test of several (but not all) versions from 1.5.5 to 4.0.1, and 1.5.5 was the only version where the Data grid handled such column names properly.
SQL Developer Team