that means the inside toolbar in expressions.can anyone with image description pl.
See attached jpeg file, hope it helps
can you pl tell me full use why it has to be used
It is used when u want to define the parameters that can be changed according to expections. For example, u have the length of a pipe defined with L and u can change it just changing the parameter L from the expressions.
It has a wide range of use but this is what it is used basically.