The Tasks setting I am using says to create an RTM task whenever I label a GMAIL message with RTM. However, only explicit labeling via the label pick list does so. Moving a message to RTM, which also labels it as RTM, does not. Granted, it is unlikely anyone will make tasks wholesale by lassoing a bunch of mail messages, but drag and drop can often be more convenient. Both modes should be supported, as the end result is a mail message labeled with RTM.