diff --git a/frontend/src/index.css b/frontend/src/index.css
index b032ef8..0b2ddd5 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -300,9 +300,43 @@ body {
   bottom: 0 !important;
   width: 100vw !important;
   height: 100vh !important;
-  z-index: 99999 !important;
+  min-width: 100vw !important;
+  min-height: 100vh !important;
+  max-width: 100vw !important;
+  max-height: 100vh !important;
+  z-index: 2147483647 !important; /* Maximum z-index value */
   margin: 0 !important;
   padding: 0 !important;
   border-radius: 0 !important;
+  border: none !important;
   background: var(--color-surface-900) !important;
+  transform: none !important;
+  box-sizing: border-box !important;
+  overflow: hidden !important;
+}
+
+/* Portal-based fullscreen editor - renders directly to body */
+.fullscreen-editor-portal {
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  width: 100vw;
+  height: 100vh;
+  z-index: 2147483647;
+  background: var(--color-surface-900);
+}
+
+/* Ensure fullscreen content fills the space */
+.fullscreen-overlay > *,
+.fullscreen-editor-portal > * {
+  max-width: 100% !important;
+  width: 100% !important;
+  height: 100% !important;
+}
+
+.fullscreen-overlay .cm-editor,
+.fullscreen-editor-portal .cm-editor {
+  height: 100% !important;
 }
diff --git a/frontend/src/pages/OpenClaw.tsx b/frontend/src/pages/OpenClaw.tsx
index 2536ce1..79dd782 100644
--- a/frontend/src/pages/OpenClaw.tsx
+++ b/frontend/src/pages/OpenClaw.tsx
@@ -1,4 +1,5 @@
 import { useEffect, useState, useCallback, useRef } from 'react';
+import { createPortal } from 'react-dom';
 import CodeMirror from '@uiw/react-codemirror';
 import { json } from '@codemirror/lang-json';
 import { markdown } from '@codemirror/lang-markdown';
@@ -10,6 +11,38 @@ import type {
 } from '../api/client';
 import { api } from '../api/client';
 
+// ═════════════════════════════════════════════════════════════════════════════════
+// Fullscreen Editor Component using Portal for true fullscreen
+// ═════════════════════════════════════════════════════════════════════════════════
+
+interface FullscreenEditorProps {
+  isOpen: boolean;
+  onClose: () => void;
+  children: React.ReactNode;
+}
+
+function FullscreenEditor({ isOpen, onClose, children }: FullscreenEditorProps) {
+  useEffect(() => {
+    if (isOpen) {
+      document.body.style.overflow = 'hidden';
+    } else {
+      document.body.style.overflow = '';
+    }
+    return () => {
+      document.body.style.overflow = '';
+    };
+  }, [isOpen]);
+
+  if (!isOpen) return null;
+
+  return createPortal(
+    <div className="fullscreen-editor-portal">
+      {children}
+    </div>,
+    document.body
+  );
+}
+
 // ═════════════════════════════════════════════════════════════════════════════════
 // Tab definitions
 // ═════════════════════════════════════════════════════════════════════════════════
@@ -625,16 +658,14 @@ function AgentsTab() {
                       })}
                     </div>
                     
-                    {/* Identity File Editor */}
-                    {activeFile?.agent === agent.name && (
-                      <div className={`border border-glass-border bg-[#282c34] overflow-hidden shadow-inner mt-4 animate-fade-in flex flex-col ${
-                        isFullscreen ? 'fullscreen-overlay' : 'h-[500px] rounded-xl relative'
-                      }`}>
-                        <div className={`flex items-center justify-between bg-surface-900/80 border-b border-glass-border shrink-0 ${isFullscreen ? 'h-16 px-6 py-4' : 'px-3 py-2'}`}>
+                    {/* Identity File Editor - Inline (not fullscreen) */}
+                    {activeFile?.agent === agent.name && !isFullscreen && (
+                      <div className="border border-glass-border bg-[#282c34] overflow-hidden shadow-inner mt-4 animate-fade-in flex flex-col h-[500px] rounded-xl relative">
+                        <div className="flex items-center justify-between bg-surface-900/80 border-b border-glass-border shrink-0 px-3 py-2">
                           <span className="text-xs font-mono text-purple-300 truncate pr-4">workspace/{agent.name}/{activeFile.file}</span>
                           <div className="flex gap-2 shrink-0">
-                            <button onClick={() => setIsFullscreen(!isFullscreen)} className="px-2 py-1 rounded text-[10px] text-gray-400 hover:bg-surface-700 hover:text-white transition-colors">
-                              {isFullscreen ? '🗗 Réduire' : '⛶ Plein écran'}
+                            <button onClick={() => setIsFullscreen(true)} className="px-2 py-1 rounded text-[10px] text-gray-400 hover:bg-surface-700 hover:text-white transition-colors">
+                              ⛶ Plein écran
                             </button>
                             <button onClick={() => { setActiveFile(null); setIsFullscreen(false); }} className="px-2 py-1 rounded text-[10px] text-gray-400 hover:bg-surface-700 hover:text-white transition-colors">
                               Fermer
@@ -660,6 +691,43 @@ function AgentsTab() {
                         )}
                       </div>
                     )}
+                    
+                    {/* Identity File Editor - Fullscreen via Portal */}
+                    {activeFile?.agent === agent.name && isFullscreen && createPortal(
+                      <div className="fullscreen-editor-portal">
+                        <div className="h-full w-full glass-card flex flex-col overflow-hidden border border-glass-border shadow-[0_40px_80px_rgb(0,0,0,0.9)] min-h-0">
+                          <div className="flex items-center justify-between bg-surface-900/80 border-b border-glass-border shrink-0 h-16 px-6 py-4">
+                            <span className="text-sm font-mono text-purple-300 truncate pr-4">workspace/{agent.name}/{activeFile.file}</span>
+                            <div className="flex gap-2 shrink-0">
+                              <button onClick={() => setIsFullscreen(false)} className="px-3 py-1.5 rounded text-xs text-gray-400 hover:bg-surface-700 hover:text-white transition-colors">
+                                🗗 Réduire
+                              </button>
+                              <button onClick={() => { setActiveFile(null); setIsFullscreen(false); }} className="px-3 py-1.5 rounded text-xs text-gray-400 hover:bg-surface-700 hover:text-white transition-colors">
+                                Fermer
+                              </button>
+                              <button onClick={saveFile} disabled={saving} className="px-4 py-1.5 rounded bg-purple-600/80 hover:bg-purple-500 text-white text-xs font-medium transition-colors">
+                                {saving ? '...' : 'Sauvegarder'}
+                              </button>
+                            </div>
+                          </div>
+                          {fileLoading ? (
+                            <div className="flex-1 flex items-center justify-center text-gray-500 text-sm animate-pulse">Chargement…</div>
+                          ) : (
+                            <div className="flex-1 overflow-auto bg-[#282c34] min-h-0">
+                              <CodeMirror
+                                value={fileContent}
+                                height="100%"
+                                theme={oneDark}
+                                extensions={[markdown()]}
+                                onChange={(val) => setFileContent(val)}
+                                basicSetup={{ lineNumbers: true, foldGutter: false, highlightActiveLine: true, tabSize: 2 }}
+                              />
+                            </div>
+                          )}
+                        </div>
+                      </div>,
+                      document.body
+                    )}
                   </div>
                 )}
 
@@ -1153,62 +1221,65 @@ function ConfigFileEditor({ onClose, onSave }: { onClose: () => void, onSave: ()
     }
   };
 
-  return (
-    <div className="fullscreen-overlay glass-card flex flex-col overflow-hidden border border-glass-border shadow-[0_40px_80px_rgb(0,0,0,0.9)] backdrop-blur-xl animate-fade-in">
-      <div className="flex items-center justify-between px-6 py-4 bg-surface-800 border-b border-glass-border shrink-0 h-16">
-        <div className="flex items-center gap-3">
-          <div className="w-10 h-10 rounded-xl bg-gradient-to-br from-amber-500/20 to-orange-600/10 border border-amber-500/20 flex items-center justify-center text-xl">
-            ✏️
+  return createPortal(
+    <div className="fullscreen-editor-portal">
+      <div className="h-full w-full glass-card flex flex-col overflow-hidden border border-glass-border shadow-[0_40px_80px_rgb(0,0,0,0.9)] backdrop-blur-xl animate-fade-in">
+        <div className="flex items-center justify-between px-6 py-4 bg-surface-800 border-b border-glass-border shrink-0 h-16">
+          <div className="flex items-center gap-3">
+            <div className="w-10 h-10 rounded-xl bg-gradient-to-br from-amber-500/20 to-orange-600/10 border border-amber-500/20 flex items-center justify-center text-xl">
+              ✏️
+            </div>
+            <div>
+              <h3 className="text-white font-bold text-base flex items-center gap-2">
+                Édition directe
+              </h3>
+              <div className="text-xs text-gray-400 font-mono mt-0.5">openclaw.json</div>
+            </div>
           </div>
-          <div>
-            <h3 className="text-white font-bold text-base flex items-center gap-2">
-              Édition directe
-            </h3>
-            <div className="text-xs text-gray-400 font-mono mt-0.5">openclaw.json</div>
+          
+          <div className="flex gap-3">
+            <button 
+              onClick={onClose} 
+              disabled={saving}
+              className="px-4 py-2 rounded-lg bg-surface-700 text-gray-300 text-sm font-medium hover:bg-surface-600 transition-colors"
+            >
+              Annuler
+            </button>
+            <button 
+              onClick={handleSave} 
+              disabled={saving}
+              className={`px-6 py-2 rounded-lg bg-gradient-to-r from-emerald-600 to-teal-600 text-white text-sm font-bold transition-all shadow-[0_0_15px_rgba(16,185,129,0.4)] flex items-center gap-2 ${saving ? 'opacity-50 scale-95 cursor-wait' : 'hover:scale-105 hover:from-emerald-500 hover:to-teal-500'}`}
+            >
+              {saving ? 'Sauvegarde...' : '💾 Sauvegarder .json'}
+            </button>
           </div>
         </div>
-        
-        <div className="flex gap-3">
-          <button 
-            onClick={onClose} 
-            disabled={saving}
-            className="px-4 py-2 rounded-lg bg-surface-700 text-gray-300 text-sm font-medium hover:bg-surface-600 transition-colors"
-          >
-            Annuler
-          </button>
-          <button 
-            onClick={handleSave} 
-            disabled={saving}
-            className={`px-6 py-2 rounded-lg bg-gradient-to-r from-emerald-600 to-teal-600 text-white text-sm font-bold transition-all shadow-[0_0_15px_rgba(16,185,129,0.4)] flex items-center gap-2 ${saving ? 'opacity-50 scale-95 cursor-wait' : 'hover:scale-105 hover:from-emerald-500 hover:to-teal-500'}`}
-          >
-            {saving ? 'Sauvegarde...' : '💾 Sauvegarder .json'}
-          </button>
-        </div>
-      </div>
 
-      <div className="flex-1 overflow-auto bg-[#282c34] min-h-0">
-        {loading ? (
-          <div className="flex items-center justify-center flex-col gap-4 h-full">
-            <span className="text-4xl animate-spin-slow opacity-50">⚙️</span>
-            <span className="text-gray-400 font-mono">Lecture de la configuration brute...</span>
-          </div>
-        ) : (
-          <CodeMirror
-            value={content}
-            height="100%"
-            theme={oneDark}
-            extensions={[json()]}
-            onChange={(val) => setContent(val)}
-            basicSetup={{
-              lineNumbers: true,
-              foldGutter: true,
-              highlightActiveLine: true,
-              tabSize: 2,
-            }}
-          />
-        )}
+        <div className="flex-1 overflow-auto bg-[#282c34] min-h-0">
+          {loading ? (
+            <div className="flex items-center justify-center flex-col gap-4 h-full">
+              <span className="text-4xl animate-spin-slow opacity-50">⚙️</span>
+              <span className="text-gray-400 font-mono">Lecture de la configuration brute...</span>
+            </div>
+          ) : (
+            <CodeMirror
+              value={content}
+              height="100%"
+              theme={oneDark}
+              extensions={[json()]}
+              onChange={(val) => setContent(val)}
+              basicSetup={{
+                lineNumbers: true,
+                foldGutter: true,
+                highlightActiveLine: true,
+                tabSize: 2,
+              }}
+            />
+          )}
+        </div>
       </div>
-    </div>
+    </div>,
+    document.body
   );
 }
 
@@ -1278,6 +1349,89 @@ function FilesystemTab() {
     return [];
   };
 
+  // Fullscreen editor via portal
+  if (isFullscreen && selectedFile) {
+    return createPortal(
+      <div className="fullscreen-editor-portal">
+        <div className="h-full w-full glass-card flex flex-col overflow-hidden border border-glass-border shadow-[0_30px_60px_rgb(0,0,0,0.9)] min-h-0">
+          <div className="p-4 bg-surface-800 border-b border-glass-border flex items-center justify-between z-10 shrink-0 h-16 px-6">
+            <div className="min-w-0 pr-4">
+              <h3 className="text-white font-medium flex items-center gap-2 text-base truncate">
+                <span className="text-xl">📄</span> {selectedFile.path.split('/').pop()}
+              </h3>
+              <div className="flex items-center gap-3 mt-1 text-[11px] text-gray-400 font-mono">
+                <span className="truncate max-w-[200px] md:max-w-xs" title={selectedFile.path}>{selectedFile.path}</span>
+                <span className="opacity-50">•</span>
+                <span>{formatSize(selectedFile.size)}</span>
+                <span className="opacity-50">•</span>
+                <span className="uppercase text-purple-300 bg-purple-500/10 px-1.5 py-0.5 rounded">{selectedFile.language}</span>
+              </div>
+            </div>
+            <div className="flex gap-2 shrink-0">
+              <button 
+                onClick={() => setIsFullscreen(false)} 
+                className="px-3 py-1.5 rounded-lg bg-surface-700 text-gray-300 text-sm hover:bg-surface-600 transition-colors flex items-center justify-center font-bold"
+                title="Réduire"
+              >
+                🗗
+              </button>
+              {!selectedFile.binary && (
+                <>
+                  {editMode ? (
+                    <>
+                      <button onClick={() => setEditMode(false)} disabled={saving} className="px-3.5 py-1.5 rounded-lg bg-surface-700 text-gray-300 text-sm hover:bg-surface-600 transition-colors">
+                        Annuler
+                      </button>
+                      <button onClick={handleSave} disabled={saving} className={`px-4 py-1.5 rounded-lg bg-gradient-to-r from-emerald-600 to-teal-600 text-white text-sm font-medium hover:from-emerald-500 hover:to-teal-500 transition-all shadow-[0_0_12px_rgba(16,185,129,0.3)] flex items-center gap-2 ${saving ? 'opacity-50 cursor-not-allowed scale-95' : 'hover:scale-105'}`}>
+                        {saving ? 'Sauvegarde…' : '💾 Sauvegarder'}
+                      </button>
+                    </>
+                  ) : (
+                    <button onClick={() => { setEditMode(true); setEditContent(selectedFile.pretty || selectedFile.content || ''); }} className="px-4 py-1.5 rounded-lg bg-gradient-to-r from-purple-600 to-indigo-600 text-white text-sm font-medium hover:from-purple-500 hover:to-indigo-500 transition-all shadow-[0_0_12px_rgba(147,51,234,0.3)] hover:scale-105 flex items-center gap-2">
+                      <span>✏️</span> Modifier
+                    </button>
+                  )}
+                </>
+              )}
+            </div>
+          </div>
+
+          <div className="flex-1 overflow-auto bg-[#282c34] min-h-0">
+            {selectedFile.binary ? (
+              <div className="flex items-center justify-center text-gray-500 bg-surface-900/60 h-full">
+                <div className="text-center">
+                  <div className="text-5xl mb-3 opacity-30">📦</div>
+                  <p className="tracking-wide">Fichier binaire. Aperçu non disponible.</p>
+                </div>
+              </div>
+            ) : editMode ? (
+              <CodeMirror
+                value={editContent}
+                height="100%"
+                theme={oneDark}
+                extensions={getExtensions()}
+                onChange={(val) => setEditContent(val)}
+                basicSetup={{
+                  lineNumbers: true,
+                  foldGutter: true,
+                  highlightActiveLine: true,
+                  tabSize: 2,
+                }}
+              />
+            ) : (
+              <div className="p-4">
+                <pre className="text-[13px] text-[#abb2bf] font-mono whitespace-pre-wrap leading-relaxed">
+                  {selectedFile.pretty || selectedFile.content}
+                </pre>
+              </div>
+            )}
+          </div>
+        </div>
+      </div>,
+      document.body
+    );
+  }
+
   return (
     <div className="flex gap-6 h-[calc(100vh-250px)] min-h-[600px]">
       {/* Sidebar Tree */}
@@ -1303,11 +1457,9 @@ function FilesystemTab() {
         </div>
       </div>
 
-      {/* Editor Panel */}
-      <div className={isFullscreen 
-        ? "fullscreen-overlay glass-card flex flex-col overflow-hidden border border-glass-border shadow-[0_30px_60px_rgb(0,0,0,0.9)] min-h-0" 
-        : "glass-card w-2/3 flex flex-col overflow-hidden border border-glass-border shadow-[0_8px_30px_rgb(0,0,0,0.5)] min-h-0"
-      }>
+      {/* Editor Panel - hidden when in fullscreen */}
+      {!isFullscreen && (
+      <div className="glass-card w-2/3 flex flex-col overflow-hidden border border-glass-border shadow-[0_8px_30px_rgb(0,0,0,0.5)] min-h-0">
         {fileLoading ? (
           <div className="flex-1 flex items-center justify-center bg-surface-900/40">
             <div className="text-gray-400 flex flex-col items-center gap-3">
@@ -1323,7 +1475,7 @@ function FilesystemTab() {
         ) : (
           <div className="flex flex-col h-full">
             {/* Editor Header */}
-            <div className={`p-4 bg-surface-800 border-b border-glass-border flex items-center justify-between z-10 shrink-0 ${isFullscreen ? 'h-16 px-6' : ''}`}>
+            <div className="p-4 bg-surface-800 border-b border-glass-border flex items-center justify-between z-10 shrink-0">
               <div className="min-w-0 pr-4">
                 <h3 className="text-white font-medium flex items-center gap-2 text-base truncate">
                   <span className="text-xl">📄</span> {selectedFile.path.split('/').pop()}
@@ -1338,11 +1490,11 @@ function FilesystemTab() {
               </div>
               <div className="flex gap-2 shrink-0">
                 <button 
-                  onClick={() => setIsFullscreen(!isFullscreen)} 
+                  onClick={() => setIsFullscreen(true)} 
                   className="px-3 py-1.5 rounded-lg bg-surface-700 text-gray-300 text-sm hover:bg-surface-600 transition-colors flex items-center justify-center font-bold"
-                  title={isFullscreen ? "Réduire" : "Plein écran"}
+                  title="Plein écran"
                 >
-                  {isFullscreen ? "🗗" : "⛶"}
+                  ⛶
                 </button>
                 {!selectedFile.binary && (
                   <>
@@ -1399,6 +1551,7 @@ function FilesystemTab() {
           </div>
         )}
       </div>
+      )}
     </div>
   );
 }