TYPO3 Core

So testing this is not that difficult but one has to understand what to do/ configure. I'm providing an example. It sets for the specific form a new themeName. When testing one will get an exception because no theme exists with this name. But the process does work.

# this is working
themeName = Mytheme

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

postProcessor {
    1 = mail
    1 {
        recipientEmail = your@mail.com
        senderEmail = your@mail.com
    }
}

10 = TEXTLINE
10 {
    name = surname
    placeholder = Surname
    required = 1
    label {
        value = Surname
    }
}

20 = SUBMIT
20 {
    name = 3
    value = Submit form
}

Setting the themeName globally does not work, i.e. you won't even get the exception since it's not evaluated.

plugin.tx_form {
    settings {
        # this is not working
        registeredElements.FORM.themeName = Mytheme
    }
}

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/43805

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/43805

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/43896