diff --git a/frontend/src/components/dms/SourceTree.tsx b/frontend/src/components/dms/SourceTree.tsx
index 228c4d2..835a283 100644
--- a/frontend/src/components/dms/SourceTree.tsx
+++ b/frontend/src/components/dms/SourceTree.tsx
@@ -4,6 +4,8 @@
  *   ▼ Meine Dateien (local folders)
  *   ▼ Geteilte Ordner (shared files from other users)
  *   ▼ Externe Speicher (placeholder for future plugins)
+ *
+ * Folders are drop targets (accept files) and draggable (for reparenting).
  */
 
 import React, { useState } from 'react';
@@ -16,6 +18,8 @@ interface SourceTreeFolderItemProps {
   level: number;
   selectedFolderId: string | null;
   onSelect: (folderId: string) => void;
+  onDropFiles: (fileIds: string[], targetFolderId: string) => void;
+  onDropFolder: (sourceFolderId: string, targetFolderId: string) => void;
 }
 
 function SourceTreeFolderItem({
@@ -23,20 +27,60 @@ function SourceTreeFolderItem({
   level,
   selectedFolderId,
   onSelect,
+  onDropFiles,
+  onDropFolder,
 }: SourceTreeFolderItemProps) {
   const { t } = useTranslation();
   const [expanded, setExpanded] = useState(true);
+  const [isDropTarget, setIsDropTarget] = useState(false);
   const hasChildren = folder.children && folder.children.length > 0;
   const isSelected = selectedFolderId === folder.id;
 
+  function handleDragOver(e: React.DragEvent) {
+    e.preventDefault();
+    e.stopPropagation();
+    e.dataTransfer.dropEffect = 'move';
+    if (!isDropTarget) setIsDropTarget(true);
+  }
+
+  function handleDragLeave(e: React.DragEvent) {
+    e.stopPropagation();
+    setIsDropTarget(false);
+  }
+
+  function handleDrop(e: React.DragEvent) {
+    e.preventDefault();
+    e.stopPropagation();
+    setIsDropTarget(false);
+    try {
+      const data = JSON.parse(e.dataTransfer.getData('application/json'));
+      if (data.type === 'files' && data.ids) {
+        onDropFiles(data.ids, folder.id);
+      } else if (data.type === 'folder' && data.id) {
+        if (data.id !== folder.id) {
+          onDropFolder(data.id, folder.id);
+        }
+      }
+    } catch {
+      // ignore invalid drop data
+    }
+  }
+
+  function handleFolderDragStart(e: React.DragEvent) {
+    e.stopPropagation();
+    e.dataTransfer.setData('application/json', JSON.stringify({ type: 'folder', id: folder.id }));
+    e.dataTransfer.effectAllowed = 'move';
+  }
+
   return (
     <li role="treeitem" aria-expanded={hasChildren ? expanded : undefined} aria-selected={isSelected}>
       <div
         className={clsx(
-          'flex items-center gap-1 px-2 py-1.5 rounded-md text-sm cursor-pointer min-h-touch',
+          'flex items-center gap-1 px-2 py-1.5 rounded-md text-sm cursor-pointer',
           'hover:bg-secondary-100 motion-safe:transition-colors',
           'focus:outline-none focus-visible:ring-2 focus-visible:ring-primary-500',
           isSelected && 'bg-primary-50 text-primary-700 font-medium',
+          isDropTarget && 'ring-2 ring-primary-400 bg-primary-50',
         )}
         style={{ paddingLeft: `${level * 12 + 8}px` }}
         onClick={() => onSelect(folder.id)}
@@ -49,6 +93,11 @@ function SourceTreeFolderItem({
         tabIndex={0}
         role="button"
         aria-label={folder.name}
+        draggable
+        onDragStart={handleFolderDragStart}
+        onDragOver={handleDragOver}
+        onDragLeave={handleDragLeave}
+        onDrop={handleDrop}
       >
         {hasChildren && (
           <button
@@ -66,7 +115,7 @@ function SourceTreeFolderItem({
           </button>
         )}
         {!hasChildren && <span className="w-4 flex-shrink-0" aria-hidden="true" />}
-        <svg className="w-4 h-4 text-warning-500 flex-shrink-0" fill="none" viewBox="0 0 24 24" stroke="currentColor" aria-hidden="true">
+        <svg className={clsx('w-4 h-4 flex-shrink-0', isDropTarget ? 'text-primary-500' : 'text-warning-500')} fill="none" viewBox="0 0 24 24" stroke="currentColor" aria-hidden="true">
           <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M3 7v10a2 2 0 002 2h14a2 2 0 002-2V9a2 2 0 00-2-2h-6l-2-2H5a2 2 0 00-2 2z" />
         </svg>
         <span className="truncate">{folder.name}</span>
@@ -75,7 +124,7 @@ function SourceTreeFolderItem({
         )}
       </div>
       {hasChildren && expanded && (
-        <ul role="group" className="space-y-0.5">
+        <ul role="group" className="space-y-0">
           {folder.children!.map((child) => (
             <SourceTreeFolderItem
               key={child.id}
@@ -83,6 +132,8 @@ function SourceTreeFolderItem({
               level={level + 1}
               selectedFolderId={selectedFolderId}
               onSelect={onSelect}
+              onDropFiles={onDropFiles}
+              onDropFolder={onDropFolder}
             />
           ))}
         </ul>
@@ -107,7 +158,7 @@ function SourceSection({ title, icon, selected, onClick, children, defaultExpand
     <div className="mb-1">
       <div
         className={clsx(
-          'flex items-center gap-1 px-2 py-1.5 rounded-md text-sm font-semibold cursor-pointer min-h-touch',
+          'flex items-center gap-1 px-2 py-1.5 rounded-md text-sm font-semibold cursor-pointer',
           'hover:bg-secondary-100 motion-safe:transition-colors',
           'focus:outline-none focus-visible:ring-2 focus-visible:ring-primary-500',
           selected && 'bg-primary-50 text-primary-700',
@@ -144,7 +195,7 @@ function SourceSection({ title, icon, selected, onClick, children, defaultExpand
         <span className="truncate">{title}</span>
       </div>
       {expanded && children && (
-        <ul role="group" className="space-y-0.5 mt-0.5">
+        <ul role="group" className="space-y-0 mt-0.5">
           {children}
         </ul>
       )}
@@ -160,6 +211,8 @@ export interface SourceTreeProps {
   onSelectFolder: (folderId: string | null) => void;
   onSelectSource: (source: string) => void;
   loading?: boolean;
+  onDropFiles: (fileIds: string[], targetFolderId: string | null) => void;
+  onDropFolder: (sourceFolderId: string, targetFolderId: string | null) => void;
 }
 
 export function SourceTree({
@@ -170,8 +223,11 @@ export function SourceTree({
   onSelectFolder,
   onSelectSource,
   loading = false,
+  onDropFiles,
+  onDropFolder,
 }: SourceTreeProps) {
   const { t } = useTranslation();
+  const [isRootDropTarget, setIsRootDropTarget] = useState(false);
 
   if (loading) {
     return (
@@ -187,15 +243,42 @@ export function SourceTree({
   const sharedSelected = selectedSource === 'shared';
   const externalSelected = selectedSource === 'external';
 
+  function handleRootDragOver(e: React.DragEvent) {
+    e.preventDefault();
+    e.dataTransfer.dropEffect = 'move';
+    if (!isRootDropTarget) setIsRootDropTarget(true);
+  }
+
+  function handleRootDragLeave(e: React.DragEvent) {
+    e.stopPropagation();
+    setIsRootDropTarget(false);
+  }
+
+  function handleRootDrop(e: React.DragEvent) {
+    e.preventDefault();
+    setIsRootDropTarget(false);
+    try {
+      const data = JSON.parse(e.dataTransfer.getData('application/json'));
+      if (data.type === 'files' && data.ids) {
+        onDropFiles(data.ids, null);
+      } else if (data.type === 'folder' && data.id) {
+        onDropFolder(data.id, null);
+      }
+    } catch {
+      // ignore invalid drop data
+    }
+  }
+
   return (
     <nav aria-label={t('dms.sources')} data-testid="source-tree" className="p-2">
-      {/* All Files entry */}
+      {/* All Files entry — also a drop target (move to root) */}
       <div
         className={clsx(
-          'flex items-center gap-2 px-2 py-1.5 rounded-md text-sm cursor-pointer min-h-touch mb-1',
+          'flex items-center gap-2 px-2 py-1.5 rounded-md text-sm cursor-pointer mb-1',
           'hover:bg-secondary-100 motion-safe:transition-colors',
           'focus:outline-none focus-visible:ring-2 focus-visible:ring-primary-500',
           selectedSource === null && selectedFolderId === null && 'bg-primary-50 text-primary-700 font-medium',
+          isRootDropTarget && 'ring-2 ring-primary-400 bg-primary-50',
         )}
         onClick={() => {
           onSelectFolder(null);
@@ -208,6 +291,9 @@ export function SourceTree({
             onSelectSource('local');
           }
         }}
+        onDragOver={handleRootDragOver}
+        onDragLeave={handleRootDragLeave}
+        onDrop={handleRootDrop}
         tabIndex={0}
         role="button"
         aria-label={t('dms.allFiles')}
@@ -244,6 +330,8 @@ export function SourceTree({
               level={0}
               selectedFolderId={selectedFolderId}
               onSelect={onSelectFolder}
+              onDropFiles={onDropFiles}
+              onDropFolder={onDropFolder}
             />
           ))
         )}
@@ -270,7 +358,7 @@ export function SourceTree({
             <li key={file.id} role="treeitem" aria-selected={false}>
               <div
                 className={clsx(
-                  'flex items-center gap-1 px-2 py-1.5 rounded-md text-sm cursor-pointer min-h-touch',
+                  'flex items-center gap-1 px-2 py-1.5 rounded-md text-sm cursor-pointer',
                   'hover:bg-secondary-100 motion-safe:transition-colors',
                 )}
                 style={{ paddingLeft: '20px' }}