If the Interest fund needs to separate the interest in accounting due to Tax regulations there should be a separate Fund Type created (otherwise Default is shown).
If the Fund Type is set to Interest the registration of transactions will have field for Bought/sold interest that needs to be filled in.
When pressing execute a Interest transaction will be created and the interest will be deducted from the amount.
The price will be adjusted to be valid without the interest. The value date of the transaction will be last day of year.
Note! If need to modify transaction make sure you modify both the buy transaction and interest transaction.
At year end the Dividend should be registered and the reinvestment of the dividend needs to be entered as a Buy transaction.