Overflow box with width as length

Overflow box 'width' 400px

1a. Float left
1b. Float right
2a.
2a.
2b. Float left
2c. Float right
3a.
3a.
3b. Float left

Gecko 1.8: Scrollable box 'width' 900px = ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px).

Gecko 1.9, Safari 3 & Opera 9.5: Scrollable box 'width' 875px = ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px~0px).

3c. Float right

Gecko 1.8 & Opera 9.5: Visible box 'width' 400px.

Gecko 1.9, Safari 3 & Opera 9.5: Scrollable box 'width' 875px = ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px~0px).

Overflow box 'padding-left' 50px + 'width' 400px + 'padding-right' 50px = 500px

4a.
4a.

Gecko 1.8: Scrollable box 'width' 975px = 'padding-left' 50px + ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px~0px) + padding-right' 50px.

Gecko 1.9 & Safari 3: Scrollable box 'width' 925px = 'padding-left' 50px + ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px~0px) + padding-right' 50px~0px.

4b. Float left

Gecko 1.8: Scrollable box 'width' 1000px = 'padding-left' 50px + ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px) + padding-right' 50px.

Gecko 1.9 & Safari 3: Scrollable box 'width' 925px = 'padding-left' 50px + ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px~0px) + padding-right' 50px~0px.

4c. Float right

Gecko 1.8~1.9: Visible box 'width' 500px.

Safari 3 (this is incorrect behavior): Scrollable box 'width' 875px = 'padding-left' 50px~0px + ('margin-left' 25px + border-left-width 25px + 'width' 800px + 'border-right-width' 25px + 'margin-right' 25px~0px) + padding-right' 50px~0px.