diff --git a/content.py b/content.py
index 2496f9136..4db8c3482 100644
--- a/content.py
+++ b/content.py
@@ -284,5 +284,6 @@ def getMentionsFromHtml(htmlText: str,matchStr="<span class=\"h-card\"><a href=\
         actorStr=mentionStr.split('"')[0]
         if actorStr.startswith('http') or \
            actorStr.startswith('dat:'):
-            mentions.append(actorStr)
+            if actorStr not in mentions:
+                mentions.append(actorStr)
     return mentions
diff --git a/webinterface.py b/webinterface.py
index 6688e5885..aaf6abd59 100644
--- a/webinterface.py
+++ b/webinterface.py
@@ -934,10 +934,12 @@ def htmlNewPost(translate: {},baseDir: str, \
         mentionDomain,mentionPort=getDomainFromActor(m)
         if not mentionDomain:
             continue
-        if mentionPort:            
-            mentionsStr+='@'+mentionNickname+'@'+mentionDomain+':'+str(mentionPort)+' '
+        if mentionPort:
+            mentionsHandle='@'+mentionNickname+'@'+mentionDomain+':'+str(mentionPort)
         else:
-            mentionsStr+='@'+mentionNickname+'@'+mentionDomain+' '
+            mentionsHandle='@'+mentionNickname+'@'+mentionDomain
+        if mentionsHandle not in mentionsStr:
+            mentionsStr+=mentionsHandle+' '
 
     # build suffixes so that any replies or mentions are preserved when switching between scopes
     dropdownNewPostSuffix='/newpost'