TYPO3 Core

I can not reproduce this. If i submit the example text this text are trimmed:

345670hd jmhdkj         hkldg fd
  gh fdf kjhfdl hgfd   
 g f

You're right. Just tested it again with the following form. One has to remember that just the first and last characters from the character list are trimmed. This is a little bit confusing within a TEXTAREA object with content spanning multiple lines.

enctype = multipart/form-data
method = post
prefix = tx_form
confirmation = 1

postProcessor {
    1 = mail
    1 {
        recipientEmail = 
        senderEmail = 
    }
}

10 = TEXTAREA
10 {
    cols = 40
    name = msg
    placeholder = Please enter your message.
    rows = 5
    filters {
        1 = trim
    }
    label {
        value = Message
    }
}

20 = TEXTAREA
20 {
    name = name
    placeholder = Please enter your name.
    filters {
        1 = trim
    }
    label {
        value = Message
    }
}

30 = SUBMIT
30 {
    name = submit
    value = Submit
}