Hi Folks,
I am using 1.5.1r2 and was also wondering about IDE line numbers, but I found that I could not see the line number reference in the bottom LHS status line (mentioned above) until I had done a "restore down" on the IDE and re-juggled the IDE's window bits'n'bobs with a "maximise" and then the status line came into view. I may have been using a "window reference" from an IDE long ago that did not show this extra bit. Try it, that is all it may require.
Anyway, I am happy (for the moment 
)
Rob