Investments can be assigned the attribute of "hidden". When an investment is hidden, it will not be displayed on the investment based graphs, nor will it be a line item in reports. It will however, continue to contribute to portfolio based figures, such as yields and portfolio value. This feature is intended to be used when you have sold all the shares in this investment, but you wish to keep it as part of your portfolio for accurate portfolio performance figures. Making the investment hidden reduces clutter when viewing your other, currently owned, investments. The visibility of hidden investments can be restored by turning on View / Hidden Investments. Set the hidden investment property with the Investment Properties - Other Dialog, or by using the Hide Sold Investments Dialog.
Investment Properties - Other Dialog