diff --git a/backend/display.py b/backend/display.py
index e6a73c5..641de20 100644
--- a/backend/display.py
+++ b/backend/display.py
@@ -42,9 +42,15 @@ XVFB_BIN = _find_bin("Xvfb")
 XDOTOOL_BIN = _find_bin("xdotool")
 IMPORT_BIN = _find_bin("import")  # ImageMagick
 XCLIP_BIN = _find_bin("xclip")
+XSEL_BIN = _find_bin("xsel")
+CLIPBOARD_BIN = XCLIP_BIN or XSEL_BIN  # prefer xclip, fallback to xsel
 
 HAS_DISPLAY_DEPS = all((XVFB_BIN, XDOTOOL_BIN, IMPORT_BIN))
 
+if not CLIPBOARD_BIN:
+    log.warning("Neither xclip nor xsel found — clipboard sync will be disabled. "
+                "Install xclip: apt-get install xclip")
+
 # Allowed command pattern — alphanumeric + hyphens only
 _SAFE_CMD = re.compile(r"^[a-zA-Z0-9][a-zA-Z0-9._\-]*$")
 
@@ -138,7 +144,7 @@ class ManagedGuiApp:
             self._capture_task = asyncio.create_task(self._capture_loop())
         if self._stderr_task is None or self._stderr_task.done():
             self._stderr_task = asyncio.create_task(self._read_stderr())
-        if XCLIP_BIN and (self._clipboard_task is None or self._clipboard_task.done()):
+        if CLIPBOARD_BIN and (self._clipboard_task is None or self._clipboard_task.done()):
             self._clipboard_task = asyncio.create_task(self._clipboard_loop())
 
     async def _read_stderr(self):
@@ -159,59 +165,126 @@ class ManagedGuiApp:
         except Exception:
             pass
 
+    async def _read_x11_selection(self, selection: str, env: dict) -> str | None:
+        """Read an X11 selection (clipboard or primary) using xclip or xsel."""
+        try:
+            if XCLIP_BIN:
+                proc = await asyncio.create_subprocess_exec(
+                    XCLIP_BIN, "-selection", selection, "-o",
+                    stdout=asyncio.subprocess.PIPE,
+                    stderr=asyncio.subprocess.PIPE,
+                    env=env,
+                )
+            elif XSEL_BIN:
+                flag = "--clipboard" if selection == "clipboard" else "--primary"
+                proc = await asyncio.create_subprocess_exec(
+                    XSEL_BIN, flag, "--output",
+                    stdout=asyncio.subprocess.PIPE,
+                    stderr=asyncio.subprocess.PIPE,
+                    env=env,
+                )
+            else:
+                return None
+            stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout=2)
+            if proc.returncode == 0 and stdout:
+                return stdout.decode(errors="replace")
+            # Log non-zero exit codes with stderr (but only once per selection to reduce noise)
+            if proc.returncode != 0 and stderr:
+                err = stderr.decode(errors="replace").strip()
+                if err and not hasattr(self, f"_logged_{selection}_err"):
+                    setattr(self, f"_logged_{selection}_err", True)
+                    log.warning("xclip %s read failed (rc=%d): %s", selection, proc.returncode, err)
+        except asyncio.TimeoutError:
+            log.warning("xclip %s read timed out for %s", selection, self.app_id)
+        except Exception as e:
+            log.warning("xclip %s read exception for %s: %s", selection, self.app_id, e)
+        return None
+
     async def _clipboard_loop(self):
-        """Poll X11 clipboard and push changes to connected browsers."""
-        if not XCLIP_BIN:
+        """Poll X11 clipboard AND primary selection, push changes to browsers.
+
+        Polls both CLIPBOARD (Ctrl+C, explicit copy) and PRIMARY (selection-based,
+        button-click copies in Electron/GTK apps) every 500ms.
+        """
+        if not CLIPBOARD_BIN:
+            log.warning("Clipboard loop skipped for %s — no xclip/xsel available", self.app_id)
             return
         env = self._display_env()
+        log.info("Clipboard loop started for %s (using %s, DISPLAY=:%d)",
+                 self.app_id, "xclip" if XCLIP_BIN else "xsel", self.display_num)
+
+        # Startup diagnostic — verify xclip can connect to the X display
+        test = await self._read_x11_selection("clipboard", env)
+        if test is not None:
+            log.info("Clipboard startup test OK for %s: got %d chars", self.app_id, len(test))
+        else:
+            log.info("Clipboard startup test for %s: empty/no owner (normal for fresh display)", self.app_id)
+
+        last_primary = ""
         while self.alive:
             try:
                 await asyncio.sleep(0.5)
                 if not self._websockets:
                     continue
-                # Read clipboard from X11
-                proc = await asyncio.create_subprocess_exec(
-                    XCLIP_BIN, "-selection", "clipboard", "-o",
-                    stdout=asyncio.subprocess.PIPE,
-                    stderr=asyncio.subprocess.PIPE,
-                    env=env,
-                )
-                stdout, _ = await asyncio.wait_for(proc.communicate(), timeout=2)
-                if proc.returncode != 0 or not stdout:
-                    continue
-                text = stdout.decode(errors="replace")
-                if text and text != self._last_clipboard:
-                    self._last_clipboard = text
-                    log.debug("Clipboard changed for %s: %d chars", self.app_id, len(text))
+
+                # Poll both CLIPBOARD and PRIMARY selections
+                new_text = None
+                for sel in ("clipboard", "primary"):
+                    text = await self._read_x11_selection(sel, env)
+                    if not text:
+                        continue
+
+                    old = self._last_clipboard if sel == "clipboard" else last_primary
+                    if text != old:
+                        if sel == "clipboard":
+                            self._last_clipboard = text
+                        else:
+                            last_primary = text
+                        new_text = text
+                        log.info("Clipboard change detected (%s selection) for %s: %d chars",
+                                 sel, self.app_id, len(text))
+                        break  # Send the first change found
+
+                if new_text:
                     dead = []
                     for ws in self._websockets:
                         try:
-                            await ws.send_json({"type": "clipboard", "data": text})
+                            await ws.send_json({"type": "clipboard", "data": new_text})
                         except Exception:
                             dead.append(ws)
                     for ws in dead:
                         self.detach_ws(ws)
-            except asyncio.TimeoutError:
-                continue
             except Exception:
+                log.warning("Clipboard loop error for %s", self.app_id, exc_info=True)
                 await asyncio.sleep(2)
+        log.info("Clipboard loop ended for %s", self.app_id)
 
     async def set_clipboard(self, text: str):
         """Write text to the X11 clipboard from the browser."""
-        if not XCLIP_BIN:
+        if not CLIPBOARD_BIN:
+            log.warning("Cannot set clipboard — no xclip/xsel available")
             return
         env = self._display_env()
         try:
-            proc = await asyncio.create_subprocess_exec(
-                XCLIP_BIN, "-selection", "clipboard",
-                stdin=asyncio.subprocess.PIPE,
-                stdout=asyncio.subprocess.PIPE,
-                stderr=asyncio.subprocess.PIPE,
-                env=env,
-            )
+            if XCLIP_BIN:
+                proc = await asyncio.create_subprocess_exec(
+                    XCLIP_BIN, "-selection", "clipboard",
+                    stdin=asyncio.subprocess.PIPE,
+                    stdout=asyncio.subprocess.PIPE,
+                    stderr=asyncio.subprocess.PIPE,
+                    env=env,
+                )
+            else:
+                proc = await asyncio.create_subprocess_exec(
+                    XSEL_BIN, "--clipboard", "--input",
+                    stdin=asyncio.subprocess.PIPE,
+                    stdout=asyncio.subprocess.PIPE,
+                    stderr=asyncio.subprocess.PIPE,
+                    env=env,
+                )
             await asyncio.wait_for(proc.communicate(input=text.encode()), timeout=2)
             self._last_clipboard = text  # prevent echo back
-            log.debug("Clipboard set from browser for %s: %d chars", self.app_id, len(text))
+            log.info("Clipboard set from browser for %s: %d chars", self.app_id, len(text))
         except Exception as e:
             log.warning("Failed to set clipboard for %s: %s", self.app_id, e)
 
diff --git a/frontend/css/apps/display.css b/frontend/css/apps/display.css
index e96886e..e2d2ec5 100644
--- a/frontend/css/apps/display.css
+++ b/frontend/css/apps/display.css
@@ -85,3 +85,69 @@
     word-break: break-word;
     white-space: pre-wrap;
 }
+
+/* Clipboard toast notification */
+.gui-clipboard-toast {
+    position: absolute;
+    top: 12px;
+    right: 12px;
+    z-index: 100;
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    padding: 8px 12px;
+    background: var(--bg-titlebar);
+    border: 1px solid var(--border-structural);
+    border-radius: var(--radius-md);
+    box-shadow: 0 4px 16px rgba(0,0,0,0.4);
+    font-family: var(--font-mono);
+    font-size: 12px;
+    color: var(--text-primary);
+    animation: gui-toast-in 0.2s ease-out;
+    max-width: 400px;
+}
+
+.gui-clipboard-toast.copied {
+    border-color: var(--status-green);
+}
+
+.gui-clipboard-toast.fade-out {
+    opacity: 0;
+    transition: opacity 0.3s ease-out;
+}
+
+@keyframes gui-toast-in {
+    from { opacity: 0; transform: translateY(-8px); }
+    to { opacity: 1; transform: translateY(0); }
+}
+
+.gui-clipboard-toast-icon {
+    flex-shrink: 0;
+    font-size: 14px;
+}
+
+.gui-clipboard-toast-text {
+    flex: 1;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+    color: var(--text-secondary);
+}
+
+.gui-clipboard-toast-btn {
+    flex-shrink: 0;
+    padding: 4px 10px;
+    background: var(--accent);
+    border: none;
+    border-radius: var(--radius-sm);
+    color: #fff;
+    font-family: var(--font-ui);
+    font-size: 11px;
+    font-weight: 500;
+    cursor: pointer;
+    white-space: nowrap;
+}
+
+.gui-clipboard-toast-btn:hover {
+    opacity: 0.9;
+}
diff --git a/frontend/js/apps/display.js b/frontend/js/apps/display.js
index 7fa1be5..937d907 100644
--- a/frontend/js/apps/display.js
+++ b/frontend/js/apps/display.js
@@ -179,6 +179,98 @@
         img.src = URL.createObjectURL(blob);
     }
 
+    // ---- Clipboard toast notification ----
+    // On HTTP (non-HTTPS), navigator.clipboard.writeText() fails silently.
+    // We show a toast with "Click to copy" so the user gesture enables clipboard write.
+
+    let _clipboardToastEl = null;
+    let _clipboardToastTimer = null;
+    let _pendingClipboardText = '';
+
+    function _showClipboardToast(state, text) {
+        _pendingClipboardText = text;
+        const container = state.container;
+        if (!container) return;
+
+        // Remove existing toast
+        if (_clipboardToastEl && _clipboardToastEl.parentNode) {
+            _clipboardToastEl.parentNode.removeChild(_clipboardToastEl);
+        }
+        clearTimeout(_clipboardToastTimer);
+
+        const toast = document.createElement('div');
+        toast.className = 'gui-clipboard-toast';
+        const preview = text.length > 60 ? text.substring(0, 60) + '…' : text;
+        toast.innerHTML = `<span class="gui-clipboard-toast-icon">📋</span>`
+            + `<span class="gui-clipboard-toast-text">${_escHtml(preview)}</span>`
+            + `<button class="gui-clipboard-toast-btn">Copy</button>`;
+
+        // Click the "Copy" button → user gesture → clipboard write guaranteed
+        const btn = toast.querySelector('.gui-clipboard-toast-btn');
+        btn.addEventListener('click', (e) => {
+            e.stopPropagation();
+            _copyToClipboard(_pendingClipboardText);
+            toast.classList.add('copied');
+            toast.querySelector('.gui-clipboard-toast-text').textContent = 'Copied!';
+            btn.style.display = 'none';
+            setTimeout(() => _removeToast(), 1200);
+        });
+
+        container.appendChild(toast);
+        _clipboardToastEl = toast;
+
+        // Auto-dismiss after 8 seconds if not clicked
+        _clipboardToastTimer = setTimeout(() => _removeToast(), 8000);
+    }
+
+    function _removeToast() {
+        clearTimeout(_clipboardToastTimer);
+        if (_clipboardToastEl && _clipboardToastEl.parentNode) {
+            _clipboardToastEl.classList.add('fade-out');
+            setTimeout(() => {
+                if (_clipboardToastEl && _clipboardToastEl.parentNode) {
+                    _clipboardToastEl.parentNode.removeChild(_clipboardToastEl);
+                }
+                _clipboardToastEl = null;
+            }, 300);
+        }
+    }
+
+    function _copyToClipboard(text) {
+        // Called from a user gesture (button click) so both APIs work
+        if (navigator.clipboard && navigator.clipboard.writeText) {
+            navigator.clipboard.writeText(text).then(() => {
+                console.log('[display] Clipboard written via Clipboard API:', text.length, 'chars');
+            }).catch(err => {
+                console.warn('[display] Clipboard API failed even with gesture:', err.message);
+                _execCommandCopy(text);
+            });
+        } else {
+            _execCommandCopy(text);
+        }
+    }
+
+    function _execCommandCopy(text) {
+        try {
+            const ta = document.createElement('textarea');
+            ta.value = text;
+            ta.style.position = 'fixed';
+            ta.style.left = '-9999px';
+            ta.style.top = '-9999px';
+            document.body.appendChild(ta);
+            ta.select();
+            document.execCommand('copy');
+            document.body.removeChild(ta);
+            console.log('[display] Clipboard written via execCommand fallback');
+        } catch (e) {
+            console.warn('[display] execCommand copy failed:', e.message);
+        }
+    }
+
+    function _escHtml(s) {
+        return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+    }
+
     function handleMessage(state, msg) {
         if (msg.type === 'closed') {
             showStatus(state, 'exited', msg.data || 'Application exited');
@@ -187,18 +279,47 @@
         } else if (msg.type === 'clipboard') {
             // X11 clipboard → browser clipboard
             const text = msg.data || '';
-            if (text && navigator.clipboard && navigator.clipboard.writeText) {
-                navigator.clipboard.writeText(text).then(() => {
-                    console.log('[display] Clipboard synced to browser:', text.length, 'chars');
-                }).catch(err => {
-                    console.warn('[display] Clipboard write failed:', err);
-                });
+            if (text) {
+                console.log('[display] Clipboard received from server:', text.length, 'chars');
+                // First try automatic write (works on HTTPS or localhost)
+                let autoWriteOk = false;
+                if (navigator.clipboard && navigator.clipboard.writeText) {
+                    navigator.clipboard.writeText(text).then(() => {
+                        console.log('[display] Clipboard auto-written via Clipboard API');
+                        // Show brief success toast
+                        _showClipboardSuccess(state);
+                    }).catch(err => {
+                        console.warn('[display] Auto clipboard write failed:', err.message);
+                        // Show interactive toast — user must click to copy
+                        _showClipboardToast(state, text);
+                    });
+                } else {
+                    // No Clipboard API (HTTP) — show interactive toast
+                    _showClipboardToast(state, text);
+                }
             }
         } else if (msg.type === 'meta') {
             // Could update title etc.
         }
     }
 
+    function _showClipboardSuccess(state) {
+        // Brief "Copied!" flash when auto-write succeeds
+        const container = state.container;
+        if (!container) return;
+        if (_clipboardToastEl && _clipboardToastEl.parentNode) {
+            _clipboardToastEl.parentNode.removeChild(_clipboardToastEl);
+        }
+        clearTimeout(_clipboardToastTimer);
+        const toast = document.createElement('div');
+        toast.className = 'gui-clipboard-toast copied';
+        toast.innerHTML = '<span class="gui-clipboard-toast-icon">✓</span>'
+            + '<span class="gui-clipboard-toast-text">Copied to clipboard</span>';
+        container.appendChild(toast);
+        _clipboardToastEl = toast;
+        _clipboardToastTimer = setTimeout(() => _removeToast(), 2000);
+    }
+
     function showStatus(state, type, text) {
         state.status = type;
         state.wrap.style.display = 'none';
diff --git a/install.sh b/install.sh
index 234dddc..b410d54 100755
--- a/install.sh
+++ b/install.sh
@@ -51,6 +51,7 @@ install_deps() {
         xvfb \
         xdotool \
         imagemagick \
+        xclip \
         x11-utils \
         libxcb-cursor0 \
         iw \