Remove selected answer when converting to comment

qa-include/app/post-update.php

@@ -876,6 +876,10 @@
 		} elseif ( ($oldanswer['type']=='A') && ($question['type']=='Q') && (($parent['type']=='Q') || ($parent['type']=='A')) ) // only if all fully visible
 			qa_post_index($oldanswer['postid'], 'C', $question['postid'], $parentid, null, $content, $format, $text, null, $oldanswer['categoryid']);
 
+		if ($question['selchildid'] == $oldanswer['postid']) { // remove selected answer
+			qa_question_set_selchildid(null, null, null, $question, null, $answers);
+		}
+
 		$eventparams=array(
 			'postid' => $oldanswer['postid'],
 			'parentid' => $parentid,