Texture paths: You can list your image search paths here. For example, after importing a complex project and placing its textures into a project specific folder, you can make all materials which use textures to work simply by adding the folder into this setting. Several folders can be defined by separating them with a semicolon. For example: 'textures;c:\tilepatterns;mytextures;'
Undo Depth: Defines the amount of successive steps recorder into the undo buffer.