Steps to reproduce:

1. Create an item that retains only trends. In the item configuration for history, choose do not store
2. Change the global housekeeping settings for history retention to use a global override.
3. Any place in the UI that calls CItemHelper::addDataSource will incorrectly change the history array key from '0' to the global housekeeping setting even though the documentation states that 'Do not store' cannot be overridden by the global housekeeper.

The svg graph widget seems to have it's own function for getGraphDataSource that correctly checks if history or trends is set to 0. The same logic must be applied in CItemHelper.

This is a blocker.