I don't khow why, but after the second responce all data replaced with new data from responce…

So, what i have:

1. Load grid:

-Type1

-Type2

-Type3

Data:

-Type1

-Type2

-Type3

2. Expand the node:

Grid:

-Type1

–Model1

–Model2

–Model3

–Model4

-Type2

-Type3

Data:

-Model1

-Model2

-Model3

-Model4

So, by clicking at the any type, it can't load any more item, because it can't find the id of clicked item…

Why it replaced all data with new response and don't add it?