diff --git a/src/components/FilePicker.tsx b/src/components/FilePicker.tsx
index df37229..25521cc 100644
--- a/src/components/FilePicker.tsx
+++ b/src/components/FilePicker.tsx
@@ -8,7 +8,9 @@ import { ModelContext, FSContext } from './contexts';
 
 export const isFileWritable = (path: string) => getParentDir(path) === '/home'
 
-function listFilesAsNodes(fs: FS, path: string): TreeNode[] {
+// export const isFileWritable = (path: string) => !path.startsWith(librariesFolder + '/');
+
+function listFilesAsNodes(fs: FS, path: string, accept?: (path: string) => boolean): TreeNode[] {
   const files: [string, string][] = []
   const dirs: [string, string][] = []
   for (const name of fs.readdirSync(path)) {
@@ -16,6 +18,9 @@ function listFilesAsNodes(fs: FS, path: string): TreeNode[] {
       continue;
     }
     const childPath = `${path}/${name}`;
+    if (accept && !accept(childPath)) {
+      continue;
+    }
     const stat = fs.lstatSync(childPath);
     const isDirectory = stat.isDirectory();
     if (!isDirectory && !name.endsWith('.scad')) {
@@ -58,7 +63,8 @@ export default function FilePicker({className, style}: {className?: string, styl
       icon: 'pi pi-home',
       label: 'User files',
       key: '/home',
-      children: listFilesAsNodes(fs, '/home'),
+      children: listFilesAsNodes(fs, '/home'),//
+      // children: listFilesAsNodes(fs, '/', f => f != librariesFolder && !f.startsWith(`${librariesFolder}/`)),
       selectable: false
     },
     {
diff --git a/src/fs/filesystem.ts b/src/fs/filesystem.ts
index 9eaded9..3344e7a 100644
--- a/src/fs/filesystem.ts
+++ b/src/fs/filesystem.ts
@@ -2,6 +2,8 @@
 
 import { zipArchives } from "./zip-archives";
 
+export const librariesFolder = '/libraries'
+
 declare var BrowserFS: BrowserFSInterface
 
 export type FSMounts = {
diff --git a/src/runner/actions.ts b/src/runner/actions.ts
index dadae26..a7a72f8 100644
--- a/src/runner/actions.ts
+++ b/src/runner/actions.ts
@@ -16,7 +16,6 @@ export const checkSyntax =
     source = '$preview=true;\n' + source;
 
     const job = spawnOpenSCAD({
-      workingDir: getParentDir(sourcePath),
       inputs: [[sourcePath, source + '\n']],
       args: [sourcePath, "-o", "out.ast"],
     });
@@ -67,7 +66,6 @@ export const render =
     
     const job = spawnOpenSCAD({
       // wasmMemory,
-      workingDir: getParentDir(params.sourcePath),
       inputs: [[params.sourcePath, source]],
       args,
       outputPaths: ['/home/out.stl']
diff --git a/src/runner/openscad-runner.ts b/src/runner/openscad-runner.ts
index 39eca33..9be83cf 100644
--- a/src/runner/openscad-runner.ts
+++ b/src/runner/openscad-runner.ts
@@ -18,7 +18,7 @@ export function createWasmMemory({maximumMegabytes, maximumBytes}: {maximumMegab
 // Output is {outputs: [name, content][], mergedOutputs: [{(stderr|stdout|error)?: string}], exitCode: number}
 export type OpenSCADInvocation = {
   wasmMemory?: WebAssembly.Memory,
-  workingDir: string,
+  // workingDir: string,
   inputs?: [string, string][],
   args: string[],
   outputPaths?: string[],