fnInCollapsedRange = function (iExpandedNodeIndex) {
			return aManuallyCollapsedServerIndexNodes.some(function (oNode) {
				return iExpandedNodeIndex > oNode.serverIndex
					&& iExpandedNodeIndex < oNode.serverIndex + oNode.magnitude;
			});
		}
Calculate the index delta till a given server-index.
Expanded nodes results in positive delta and collapsed note results in negative one.

A collapsed node contributes to the delta when it meets the following conditions:
 1. it's not a manually expanded node.
 2. it's not contained in the range of another collapsed node

An expanded node contributes to the delta when it meets the following conditions:
 1. it's not expanded with the initial call which means it's either initially collapsed or manually loaded
 2. none of its ancestor it's collapsed.

@param {number} iEndServerIndex The server index
@returns {number} The index delta

@private