[Eric] use tabs for indentations strange behavior

[Laurent Dufréchou]

Hi detlev,

If i use 'use tabs for indentations' there is a strange bug.
Let see:
If the option is deselected.
Than you edit a new .py file.
all is ok with indentation.

Now if you activate the option (with newly edited file always open).
Each time you add a tab, there is an indentation error!

The opposite is not true:
If you start a new file with option selected and you write some code, 
then you deselect the option, further tabulation don't do indentation 
errors.
not a so big bug but really boring for newcomers at first configuration ;)

Laurent