According to this article the default filter on message 'body' only works for POP accounts: you have to define a header for IMAP. Is that relevant to your problem? http://kb.mozillazine.org/Filters_(Thunderbird)

it does not work on emails stored in the Infolder, after they have been received. Also, I asked for a solution, not another question.'Sorry if I asked too much of this community.

Why are you creating another question ? This causes much repetition and confusion with the conversation. This is a link to the original question, which at the time was awaiting a reponse from you. for the benefit of anyone seeing this, you can read the first part of the converation at the link: https://support.mozilla.org/en-US/questions/1135022

We understand your frustration, but there is no need to be rude to people who try to help. There is no obligation on any volunteer to assist if you are not polite.

I'm presuming this is a POP mail account because you selected to perform the action to delete off pop server which would not have been available for imap.

You have already been advised that these types of 'Junk' are best dealt with by setting up Junk controls, training them to deal with these types of mail which will alter in small ways to get the emails into your inbox.

For the benefit of anyone reading this - I'm trying to identify what has been selected as it is in swedish. You have selected manual and getting new mail. I notice you are using 'Filter before Junk classification', so not allowing these emails to be dealt with by Junk controls which are designed to handle them.

I notice you have the option: 'Match any of the following' You only have one condition so should select 'Match all of the following'.

In google translate, Meddelande translates as message - I presume this is 'Body' in English versions and you use the 'contains' option.

at the bottom of filter this is mentioned: NOTE filter Measures will run in a different order see the execution order

Explanation: Filters are executed in the order they appear in the list of filters, except when that order is not possible, in which case you will see the message Note: Filter actions will be run in a different order, and the link See execution order. If you click the link, you will see which order is used. It is likely to say the pop deletion will operate first.

Swap those two actions - select to delete off pop first and then delete message.

I notice the email is already in the 'Inbox'. I notice that 'test' message filter is one of many - move it to the top of the list. Please uncheck/disable all other filters, so that only 'test' is enabled. At the bottom click on 'Filter log' select the option to 'Enable the filter log' click on 'Clear log' button. click on 'Close'

At the bottom - 'run selected message filters on': select the Inbox on mail account click on 'Run Now'

What happens ? click on 'Filter log' button - what is shown in the filter log window ?