I've just started using this excellent piece of software and I'm generally very satisfied. Kudos to the developers!

I've created several income categories, but realized that I actually do not need one of them. I'd like to delete it. The problem is that the Delete category option is disabled when right clicking the category in the Categories view. I guess that the reason is that it is involved in a scheduled transaction or used somehow in a different place. However, I am unable to find where it is used. The category's ledger is empty.

How can I delete the category?

Thank you.

First of all, which version are you using? The behavior for that particular action has changed in the latest versions.
You should be able to delete it in the Categories View. If there were still a transaction assigned to that category, you would be prompted to reassign it to a new category.

I'm using version 1.0.2. As I said, the "Delete category..." option is disabled, so there is no prompt. There are some other categories that do not have the option disabled.

Is there something unique in those categories that are disabled for deletion?

There are 9 income categories, 3 of which are disabled for deletion. I couldn't find anything unique about them. 1 of them has child categories, the other two do not. Some are included in a budget, others are not. Some have transactions, some do not. I can't find a pattern.

Are any of these categories included in scheduled transactions?

One of them is included in a scheduled transaction.

Is there a simpler way to check this than opening every single scheduled transaction and reading the category field?

Saving as .xml, looking for category Id, and then looking for that Id in the whole file.

But that depends on your definition of simple.

Yes, that's much simpler.

I found the cause of the issue by searching through the XML. The category that was disabled for deletion was set as the default category for a payee. Once I changed the payee's default category to another one, I was able to delete the problematic category. Thank you for helping me with this issue!

Is this a bug or an expected behavior?

It is expected behavior, although we have to work on usability to warn the user about this kind of stuff.

Allowing you to remove the category when it is still a default category could cause a problem later, that's why it's disabled.