TYPO3 Powermail Issue on textarea with active confirmation page

powermail-textarea_multiline-confirmation_page.diff

diff -ru a/Resources/Private/Templates/Form/Confirmation.html b/Resources/Private/Templates/Form/Confirmation.html
--- a/Resources/Private/Templates/Form/Confirmation.html	2017-08-22 12:03:56.823729265 +0200
+++ b/Resources/Private/Templates/Form/Confirmation.html	2017-08-22 12:23:34.000000000 +0200
@@ -68,7 +68,14 @@
 				</f:for>
 			</f:then>
 			<f:else>
-				<f:form.hidden property="{answer.field.marker}" value="{answer.value}" />
+				<f:if condition="{answer.field.type} == 'textarea'">
+					<f:then>
+						<f:form.textarea style="visibility:hidden;position:absolute;" property="{answer.field.marker}" value="{answer.value}" />
+					</f:then>
+					<f:else>
+						<f:form.hidden property="{answer.field.marker}" value="{answer.value}" />
+					</f:else>
+				</f:if>
 			</f:else>
 		</f:if>
 	</f:for>

That is an issue of ext:sourceopt - not of powermail.
See in2code-de/powermail#148