We have a known problem of cumulative round-off error for default tabs, 
which gets especially bad at certain DPIs -- ie, most zoom factors other 
than 100% on Windows, and even at 100% on GTK.  To see this behavior, look 
for misaligned tick marks running along the bottom of the top ruler.  They 
happen to line up perfectly with where the formatter puts those tabs, which 
is *not* where the ruler (accurately) wants them to be.  
That problem should be quite easy to fix.  However, I suspect you're 
referring to a far more insidious problem. 
>What is the priority for this. Is it required to be fixed for release 1.0.
Technically, a word processor that isn't truly WYSIWYG doesn't meet our 
design criterion of a product that:
  Just Works, out of the box, as expected
To date, our heads have been collectively planted in the sand on this issue, 
and given the amount of work already on everyone's plate, I wouldn't have 
been surprised to see this feature slip for 1.0.  
>I'll be willing to look at this problem.
Ah, the magic words.  :-)  Please do.  
We'd certainly prefer to have you nail it now, if you feel up to it.  If the 
solution becomes too unmanageable, we can always defer it for a subsequent 
release.  
Paul