scenario:

(when using phpstorm 2016.2)

you have an array with the following structure (note last element is indexed '0'):

array(5) {
[1]=>
string(5) "first"
[2]=>
string(6) "second"
[3]=>
string(5) "third"
[4]=>
string(5) "forth"
[0]=>
string(4) "test"
}

when you set a breakpoint, freeze the code and inspect the array in the debug window.

The array will be displayed as:

0 = "test"
1 = "first"
2 = "second"
3 = "third"
4 = "forth"

instead of

1 = "first"
2 = "second"
3 = "third"
4 = "forth"
0 = "test"