The calc_percent( int width ) function in css_length.h casts percentages down to integers. In a way this is fine ( for rendering ) but it looks like these integer values are being used in calculations for relative positioned divs. Here's an example:

______________________________________________________
|     ___________           __________               |
|     | div 1   |           | div 2  |         ...   |
|     -----------           ----------               |
|                                                    |
|                                                    |
------------------------------------------------------

Imagine div 1 is positioned at 33,3px from the left side of the screen. it has a width of 56,9px, div 2 is positioned 60,8px from div1.
If you keep the fractions, you get a final position for div 2 of : 33.3 + 56.9 + 60.8 = 151
If you round down each value however, you get a final position of 33 + 56 + 60 = 149

This is already a difference of 2 pixels..

_Possible solutions:_

• keep the fraction during the position calculations and round them down when rendering
• Use integers but use 32 units to represent 1 pixel. then you can divide by 32 ( or shift ) when you render, to use the rounded position.