I currently have the following accounts categorized this way:

Gain of FX

Investment Gains

Loss of FX

Investment Losses

I want to change the account types so that Gain / Loss of FX is under Operating Income / Expense and Investment Gains / Losses is under Non Operating Income / Expense.

This way the Profit & Loss reports show up correctly.

Right now when I try to change the "Account Type" is grayed out, so I assume this can't be changed this easily. But there should be a way to do it, for example by creating a new Account and migrating statements.