In Canada, when you sell part of your holdings, you cannot select a lot from your holdings and calculate your profit and loss based on that lot. All your holdings in a particular stock are considered to be one pool of identical assets, and gain/loss is calculated based on the average cost of the entire holdings of the stock.
If the folder representing the entire holdings of a stock is selected, jStock does not allow a sell transaction for less than the entire holdings. If a particular lot is selected, jStock calculates the gain/loss on the sale based on that lot's cost. This causes incorrect results for use in Canada.