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frontend/src/sidebar/Sidebar.jsx

@@ -165,6 +165,7 @@ const Sidebar = ({
   onCreateFolder,
   creatingFolder = false,
   tags = [],
+  untaggedFilterId = null,
   activeTagIds = [],
   onToggleTagFilter,
   correspondents = [],
@@ -215,6 +216,7 @@ const Sidebar = ({
   );
   const handleToggleTag = onToggleTagFilter || (() => {});
   const activeTagSet = new Set(activeTagIds);
+  const untaggedActive = untaggedFilterId ? activeTagSet.has(untaggedFilterId) : false;
   const handleManageTags = onManageTags || (() => {});
   const handleManageCorrespondents = onManageCorrespondents || (() => {});
   const handleCreateTag = useCallback(async () => {
@@ -619,6 +621,20 @@ const Sidebar = ({
             }`}
             role="list"
           >
+            {untaggedFilterId ? (
+              <button
+                type="button"
+                role="listitem"
+                className={`sidebar-tag-pill sidebar-tag-pill--untagged${
+                  untaggedActive ? ' active' : ''
+                }`}
+                onClick={() => handleToggleTag(untaggedFilterId)}
+                aria-pressed={untaggedActive}
+                draggable={false}
+              >
+                No tag assigned
+              </button>
+            ) : null}
             {tags.map((tag) => {
               const isActive = activeTagSet.has(tag.id);
               const style = getTagColorStyle(tag.color);