I have two elements in one frame and if I use:
It shows me 0 and 1, It is all right!
But if I don't select two of them , the depth is 2 and 2!
How it possible!!!!!
Is it a bug?
It works correctly for me. Can you share your test file along with the steps so that we can have a look at what's going wrong for you?
Please note that simple shapes(unselected) at the same layer have the same depth. If you have a drawing object or a symbol instead, then their deapth would be different.