[racket] DrRacket editor behaviour change

In version 5.3.1 if I'm on line 90 and I press:
CTRL+SHIFT+HOME - all text to the beginning of the file is selected.
If I then press the down arrow twice the first 2 lines of text (at the 
beginning of the file) are removed from the selection.

Similarly with selecting to the beginning of a line with just SHIFT+HOME 
and then adjusting using right arrow.

In version 5.3.2/5.3.3 with the same keystrokes I get different behaviour.
CTRL+SHIFT+HOME - all text to the beginning of the file is selected
If I then press down arrow twice the selected text extends to include 
lines 91 and 92 instead of de-selecting the first 2 lines of the file.

I'm so used to the previous behaviour that this is causing me great 
frustration and many mistakes.
The behaviour of other editors hasn't changed - so I don't think it's a 
library issue.

Has something changed in the DrRacket editor?
How do I get back the previous behaviour?

I'm using Arch Linux 64 bit
Kernel - 3.8.3-2

Thanks for any help.
Bhrgunatha