SQL Developer

This is the steps I followed in SQL Worksheet :

Execute SELECT STREET1, A.* FROM ADDRESS A
Move the column STREET1 in the Results to be the third column
Execute once again Execute SELECT STREET1, A.* FROM ADDRESS A
STREET1 will always come as the third column even if the STREET1 column is the first column in the select statement
Modify the scripts and run it SELECT STREET1, STREET2, A.* FROM ADDRESS A
Re-Execute SELECT STREET1, A.* FROM ADDRESS A
The STREET1 column is still the third column
Run any other query, but if I run the first query, the column will always be the third column.
I deleted a space before A. and re-ran it. STREET1 is now the first column
I added a space before A. and re-ran it. STREET1 is now back as a third column

Is this an expected behaviour, or is it a bug ?

Environment :Windows XP & SQL Developer V 1.0.0.11.84 Build MAIN-11.84

-Nags