Steps to reproduce:

1. The topN widget isn't showing the topN or bottomN values properly for me.
2. I'm trying to sort a floating point field, of ptp ofsets which show time down to mcroseconds.   I'd like to see which hosts have the worst offsets, which is actually really useful in determining network buffering and network application issues...  Not to mention its important if you have a lot of data going between hosts and you need to look at timestamps of data in various places....  
3. In any event, and it looks like the zabbix widget sorts a 64 bit signed number as scientific notation with the sorting on the mantissa (2.6e-10 vs 3.5e-9 it will home in on 2.6 and 3.5 as an example): 

Result:
See screenshots..  I provided a top screenshot as well as a "bottom 12" screenshot.

Expected:
Properly sorted; which it is not...!