loosing selection of region

[sandro dentella]

Hi,

  since I moved to ubuntu emacs behave a  little bit different. One of
these differences is very annoying. In many situation I loose the
region definition. E.g.: if I 'indent-rigidly' (bound to C-x C-i)
after the first time I loose the
definition of the region and I cannot go any further.

Similarly, if I mark a point and extend it using C-n, the moment it
arrives at the end of the file it forgets the position of the mark,
and no region gets selected.

Is there some settings that control this?

TIA
sandro
*:-)