Fixed freedomofpress#61 and supercedes freedomofpress#685

securedrop_client/gui/widgets.py

@@ -2419,6 +2419,9 @@ def __init__(self, source_db_object: Source, controller: Controller):
         self.scroll.setWidget(self.container)
         self.scroll.setWidgetResizable(True)
 
+        # Flag to show if the current user has sent a reply. See issue #61.
+        self.reply_flag = False
+
         # Completely unintuitive way to ensure the view remains scrolled to the bottom.
         sb = self.scroll.verticalScrollBar()
         sb.rangeChanged.connect(self.update_conversation_position)
@@ -2490,11 +2493,9 @@ def update_conversation_position(self, min_val, max_val):
         Handler called when a new item is added to the conversation. Ensures
         it's scrolled to the bottom and thus visible.
         """
-        current_val = self.scroll.verticalScrollBar().value()
-        viewport_height = self.scroll.viewport().height()
-
-        if current_val + viewport_height > max_val:
+        if self.reply_flag and max_val > 0:
             self.scroll.verticalScrollBar().setValue(max_val)
+            self.reply_flag = False
 
     def add_message(self, message: Message, index) -> None:
         """
@@ -2544,6 +2545,7 @@ def on_reply_sent(self, source_uuid: str, reply_uuid: str, reply_text: str) -> N
         """
         Add the reply text sent from ReplyBoxWidget to the conversation.
         """
+        self.reply_flag = True
         # TODO: replace this with UI indication that the reply is "in flight"
         # For now, just do nothing.
         # if source_uuid == self.source.uuid: