Many Freeway users want to use a graphic item in the background which has a color applied to it. This will look fine on the Freeway page, but the background may break apart and display with lines or blocks in it.
This is caused by the slight differences in the default font size from one browser to another, and also from the Mac platform to the PC platform. If the default font size increases (which is common with PC browsers), this will force the background to break apart.
To fix this, use an HTML item instead of a graphic item - as this won't break apart.
The simplest way to do this is to select the background item, go to the Output tab of the Inspector and change the "Type" to HTML.