[TYPO3-core] Strage behaviour of latest TCEforms version

[Sebastian Kurfuerst]

Hi Bernhard & everyone,

I revisited all my changes I did to TCEforms regarding this issue and
changed the behavior at some places - there was some part of an
if-clause I overlooked when I first created the patch, and I now found
out about the issue.
I am quite confident it all works now as expected. Sorry again that this
patch made so much trouble, it was one of my first changes I did to
TYPO3 core.

Greets, Sebastian