Index: trunk/src/org/openstreetmap/josm/gui/io/UploadDialogModel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/io/UploadDialogModel.java	(revision 18823)
+++ trunk/src/org/openstreetmap/josm/gui/io/UploadDialogModel.java	(revision 18824)
@@ -76,9 +76,9 @@
      */
     String findHashTags(String comment) {
-        String hashtags = Arrays.stream(comment.split("\\s", -1))
+        String foundHashtags = Arrays.stream(comment.split("\\s", -1))
             .map(s -> Utils.strip(s, ",;"))
             .filter(s -> s.matches("#[a-zA-Z0-9][-_a-zA-Z0-9]+"))
-            .collect(Collectors.joining(";"));
-        return hashtags.isEmpty() ? null : hashtags;
+            .distinct().collect(Collectors.joining(";"));
+        return foundHashtags.isEmpty() ? null : foundHashtags;
     }
 
@@ -96,5 +96,7 @@
                 Set<String> sanitizedHashtags = new LinkedHashSet<>();
                 for (String hashtag : hashtags.split(";", -1)) {
-                    sanitizedHashtags.add(hashtag.startsWith("#") ? hashtag : "#" + hashtag);
+                    if (comment == null || !comment.contains(hashtag)) {
+                        sanitizedHashtags.add(hashtag.startsWith("#") ? hashtag : "#" + hashtag);
+                    }
                 }
                 if (!sanitizedHashtags.isEmpty()) {
@@ -108,5 +110,5 @@
     /**
      * Inserts/updates/deletes a tag.
-     *
+     * <p>
      * Existing keys are updated. Others are added. A value of {@code null}
      * deletes the key.
@@ -131,5 +133,5 @@
     /**
      * Inserts/updates/deletes a tag.
-     *
+     * <p>
      * Existing keys are updated. Others are added. A value of {@code null}
      * deletes the key.
@@ -147,5 +149,5 @@
     /**
      * Inserts/updates/deletes all tags from {@code map}.
-     *
+     * <p>
      * Existing keys are updated. Others are added. A value of {@code null}
      * deletes the key.
Index: trunk/src/org/openstreetmap/josm/gui/tagging/presets/TaggingPresetSelector.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/tagging/presets/TaggingPresetSelector.java	(revision 18823)
+++ trunk/src/org/openstreetmap/josm/gui/tagging/presets/TaggingPresetSelector.java	(revision 18824)
@@ -20,5 +20,4 @@
 import java.util.Set;
 import java.util.regex.Pattern;
-import java.util.stream.Collectors;
 
 import javax.swing.AbstractAction;