Don't attempt jingle file transfers in MUCs

libdino/src/service/chat_interaction.vala

@@ -196,6 +196,8 @@ public class ChatInteraction : StreamInteractionModule, Object {
         XmppStream? stream = stream_interactor.get_stream(conversation.account);
         if (stream == null) return;
 
+        if (message.stanza_id != null) return; // Need a stanza id to mark
+
         switch (marker) {
             case Xep.ChatMarkers.MARKER_RECEIVED:
                 if (stanza != null && Xep.ChatMarkers.Module.requests_marking(stanza)) {

libdino/src/service/jingle_file_transfers.vala

@@ -163,6 +163,9 @@ public class JingleFileSender : FileSender, Object {
     }
 
     public bool can_send(Conversation conversation, FileTransfer file_transfer) {
+
+        if (conversation.type_ == Conversation.Type.GROUPCHAT) return false;
+
         // No file specific restrictions apply to Jingle file transfers
         return is_upload_available(conversation);
     }