diff --git a/frontend/src/reports/editor/EditorMenu.svelte b/frontend/src/reports/editor/EditorMenu.svelte
index e53099f48..0c9370af1 100644
--- a/frontend/src/reports/editor/EditorMenu.svelte
+++ b/frontend/src/reports/editor/EditorMenu.svelte
@@ -14,7 +14,10 @@
   import AppMenu from "./AppMenu.svelte";
   import AppMenuItem from "./AppMenuItem.svelte";
   import AppMenuSubItem from "./AppMenuSubItem.svelte";
+  import File from "./File.svelte";
+  import Folder from "./Folder.svelte";
   import Key from "./Key.svelte";
+  import { source_tree } from "./treeview";
 
   export let file_path: string;
   export let editor: EditorView;
@@ -33,18 +36,17 @@
       editor.focus();
     }
   }
+  $: [filenodes, foldernodes] = source_tree(sources, goToFileAndLine);
 </script>
 
 <div class="fieldset">
   <AppMenu>
     <AppMenuItem name={_("File")}>
-      {#each sources as source}
-        <AppMenuSubItem
-          action={() => goToFileAndLine(source)}
-          selected={source === file_path}
-        >
-          {source}
-        </AppMenuSubItem>
+      {#each filenodes as file}
+        <File {file} {file_path} />
+      {/each}
+      {#each foldernodes as folder}
+        <Folder {folder} {file_path} force_expand />
       {/each}
     </AppMenuItem>
     <AppMenuItem name={_("Edit")}>
diff --git a/frontend/src/reports/editor/File.svelte b/frontend/src/reports/editor/File.svelte
new file mode 100644
index 000000000..6aeb499c1
--- /dev/null
+++ b/frontend/src/reports/editor/File.svelte
@@ -0,0 +1,28 @@
+<script lang="ts">
+  import type { FileNode } from "./treeview";
+
+  export let file: FileNode;
+  export let file_path: string;
+</script>
+
+<span class:selected={file.path === file_path}>
+  <button type="button" on:click={file.action}>
+    {file.name}
+  </button>
+</span>
+
+<style>
+  .selected::before {
+    content: "›";
+  }
+
+  span {
+    padding: 2px 0;
+    cursor: pointer;
+  }
+
+  button {
+    display: contents;
+    color: blue;
+  }
+</style>
diff --git a/frontend/src/reports/editor/Folder.svelte b/frontend/src/reports/editor/Folder.svelte
new file mode 100644
index 000000000..735c00787
--- /dev/null
+++ b/frontend/src/reports/editor/Folder.svelte
@@ -0,0 +1,67 @@
+<script lang="ts">
+  import File from "./File.svelte";
+  import type { FolderNode } from "./treeview";
+
+  export let force_expand = false;
+  export let folder: FolderNode;
+  export let file_path: string;
+</script>
+
+<div class:force-expand={force_expand}>
+  <span>{folder.name}</span>
+
+  <ul>
+    {#each folder.subfiles as file}
+      <li>
+        <File {file} {file_path} />
+      </li>
+    {/each}
+    {#each folder.subfolders as subfolder}
+      <li>
+        <svelte:self folder={subfolder} {file_path} />
+      </li>
+    {/each}
+  </ul>
+</div>
+
+<style>
+  span {
+    padding: 2px 0;
+    font-weight: bold;
+    cursor: pointer;
+  }
+
+  ul {
+    padding: 0.2em 0 0 1em;
+    margin: 0 0 0 0.27em;
+    list-style: none;
+  }
+
+  li {
+    padding: 0.2em 0;
+  }
+
+  div {
+    display: inline-block;
+  }
+
+  div > ul {
+    display: none;
+  }
+
+  div:hover > ul,
+  div.force-expand > ul {
+    display: block;
+  }
+
+  div:not(:hover, .force-expand) > span::before {
+    font-family: monospace;
+    content: "+";
+  }
+
+  div:hover > span::before,
+  div.force-expand > span::before {
+    font-family: monospace;
+    content: "-";
+  }
+</style>
diff --git a/frontend/src/reports/editor/treeview.ts b/frontend/src/reports/editor/treeview.ts
new file mode 100644
index 000000000..c222c054f
--- /dev/null
+++ b/frontend/src/reports/editor/treeview.ts
@@ -0,0 +1,90 @@
+export interface FileNode {
+  name: string;
+  path: string;
+  action: () => void;
+}
+export interface FolderNode {
+  name: string;
+  subfolders: FolderNode[];
+  subfiles: FileNode[];
+}
+
+const zip: <A, B>(a: A[], b: B[]) => [A, B][] = <A, B>(a: A[], b: B[]) =>
+  a.reduce((l: [A, B][], k: A, i) => {
+    const n = b[i];
+    if (n !== undefined) {
+      l.push([k, n]);
+    }
+    return l;
+  }, []);
+
+function shorten_folder(folder: FolderNode): FolderNode {
+  if (folder.subfiles.length === 0) {
+    const subfolder = folder.subfolders[0];
+    if (subfolder !== undefined) {
+      const new_name = `${folder.name}/${subfolder.name}`;
+      return shorten_folder({
+        name: new_name,
+        subfolders: subfolder.subfolders,
+        subfiles: subfolder.subfiles,
+      });
+    }
+  }
+  return {
+    name: folder.name,
+    subfolders: folder.subfolders.map(shorten_folder),
+    subfiles: folder.subfiles,
+  };
+}
+function _source_tree(
+  paths: string[][],
+  filenodes: FileNode[]
+): [FileNode[], FolderNode[]] {
+  const groupBy = <T>(arr: T[], key: (i: T) => string) =>
+    arr.reduce<Record<string, T[]>>((groups, item) => {
+      (groups[key(item)] ||= []).push(item);
+      return groups;
+    }, {});
+
+  const r1 = zip(filenodes, paths)
+    .filter((a) => a[1].length === 0)
+    .map((a) => a[0]);
+  const r2 = Object.entries(
+    groupBy(
+      zip(filenodes, paths).reduce(
+        (acc: [FileNode, string[], string][], [file, path]) => {
+          const root = path[0];
+          if (root !== undefined) {
+            acc.push([file, path.slice(1), root]);
+          }
+          return acc;
+        },
+        []
+      ),
+      (a: [FileNode, string[], string]) => a[2]
+    )
+  ).map(([dir, group]: [string, [FileNode, string[], string][]]) => {
+    const [subfiles, subfolders] = _source_tree(
+      group.map((a: [FileNode, string[], string]) => a[1]),
+      group.map((a: [FileNode, string[], string]) => a[0])
+    );
+    return { name: dir, subfolders, subfiles };
+  });
+  return [r1, r2];
+}
+export function source_tree(
+  files: string[],
+  goToFileAndLine: (filename: string, line?: number) => void
+): [FileNode[], FolderNode[]] {
+  files.sort();
+  const paths = files.map((file) => file.split("/"));
+  const raw_filenodes = zip(files, paths).map(
+    ([file, path]: [string, string[]]) => ({
+      name: path.pop() ?? file,
+      path: file,
+      action: () => goToFileAndLine(file),
+    })
+  );
+  const [filenodes, foldernodes] = _source_tree(paths, raw_filenodes);
+  return [filenodes, foldernodes.map(shorten_folder)];
+}