This action event can be used to modify the start texturing offset for objects that use a texturing fill style. This can be useful to create a scrolling texture effect or something similar. It's also possible to leave one of the text widgets empty in which case the offset is only modified in one direction.
You can also use variable names instead of numeric constants with this action event. It is even possible to enter complete expressions like "x+1" or function calls for maximum flexibility here.