nsSprocketLayout::Layout lays out its children by looping from first child to last child updating local variables x, y as it goes that keep track of the position where to layout the current child.
If the box is horizontal it works left-to-right or right-to-left according to wheather the direction of the box is normal or not. Vertical boxes work similarly top-to-bottom or bottom-to-top. Vertical boxes also respond to CSS direction styles, so that in an LTR box the child boxes are laid out flush left, but flush right in an RTL box. Herein lies the bug, some code assumes the child boxes are laid out flush right in RTL, but the code to actually position the children positions them flush left.
The code that assumes the child are laid out flush right is HandleBoxPack, which determines the origin to start laying out children at, and the code which uses HandleBoxPack to determine if the origin changed during the laying out of the children, and then shifts the children by the amount the origin shifted. The size of our box changing will, in general, change the position of the origin. So the children aren't laid out to the origin that HandleBoxPack expects they will get moved to wrong positions.
nsSprocketLayout::Layout lays out its children by looping from first child to last child updating local variables x, y as it goes that keep track of the position where to layout the current child.
If the box is horizontal it works left-to-right or right-to-left according to wheather the direction of the box is normal or not. Vertical boxes work similarly top-to-bottom or bottom-to-top. Vertical boxes also respond to CSS direction styles, so that in an LTR box the child boxes are laid out flush left, but flush right in an RTL box. Herein lies the bug, some code assumes the child boxes are laid out flush right in RTL, but the code to actually position the children positions them flush left.
The code that assumes the child are laid out flush right is HandleBoxPack, which determines the origin to start laying out children at, and the code which uses HandleBoxPack to determine if the origin changed during the laying out of the children, and then shifts the children by the amount the origin shifted. The size of our box changing will, in general, change the position of the origin. So the children aren't laid out to the origin that HandleBoxPack expects they will get moved to wrong positions.
Timothy Nikkel
Ryan VanderMeulen