The entry of capital gains and losses outlined in section 8.7 of the Concepts guide needs a note to clearly explain to users that data for this split must be input using the Tab key, as opposed to the Enter key. Gnucash will not correctly create the splits if the Enter key is used. As a basic step to assist with this, I recommend something like the following text, to be inserted just after the second paragraph:

Note: In order to get &app; to commit this zero-share, zero-price split to the transaction, you *must* Tab out of the split. If you use the Enter key, &app; will convert the split into shares of the commodity.