Desktop wallet: getrawmempool does not work properly

I tried rpc from .net application but it has the same problem when use wallet->help->debug window->console.
When call getrawmempool it returns transaction ids in memory pool. That is correct.
But if I use `getrawmempool true` to get transactions with details it I got the error: 
```
getrawmempool
Returns all transaction ids in memory pool. (code -1)
```
