While attempting to change a category, either in a new transaction or wishing to change a category in an existing transaction, once the category is selected, it can not be deleted/changed. It can only be added to. Yes, the category can be deleted under preferences, but that certainly is not convenient.
This solution for deleting a category from a transaction doesn't work for me. When I click on Options, then Edit, the standard "fly out" opens. Clicking on the Category field only toggles the list of categories. You must then click on Cancel or Save to access the uncheck column. Please try a different way of explaining this.
Can you please clarify what exactly are you trying to do?
To change an existing category that has been previously selected from the category dropdown menu:
1-click the category field and when the dropdown menu appears click on the
same category that you want to remove from the transaction.
2-click on the category field within the transaction window and 'none' will appear.
3-click on the category field and select the correct category.
You can eliminate one step by clicking on the correct category after you have clicked on the category you wish to change. Then click on the transaction category field and your new corrected category will appear.
Hope this helps.