The Texture Left variable controls the left pixel of the source rectangle used to draw the NineSlice. Texture Left is only available if the NineSlice uses a Texture Address of Custom or Dimension Based.
The following image shows a NineSlice with a Texture Left value of 96.
Texture Left controls the left side of the region that the NineSlice displays on its source file. In this case, the left-edge of the source rectangle is 96 pixels from the left edge of the entire file.
