diff --git a/src/main/window/createMainWindow.ts b/src/main/window/createMainWindow.ts
index 11543dadf93..e3cbecdf509 100644
--- a/src/main/window/createMainWindow.ts
+++ b/src/main/window/createMainWindow.ts
@@ -655,10 +655,20 @@ export function createMainWindow(
   const onPopupMenu = (): void => {
     Menu.getApplicationMenu()?.popup({ window: mainWindow })
   }
+  // Why: the renderer's WindowControls mounts after ready-to-show, which is
+  // also when savedMaximized is restored — so window:maximize-changed has
+  // already fired (or not fired, if maximize() was called pre-mount) before
+  // the listener attaches. Expose a synchronous getter so the button can
+  // initialize its icon to match the current state on mount.
+  const isMaximizedChannel = 'window:isMaximized'
+  const onIsMaximized = (): boolean => {
+    return !mainWindow.isDestroyed() && mainWindow.isMaximized()
+  }
   ipcMain.on(minimizeChannel, onMinimize)
   ipcMain.on(maximizeChannel, onMaximize)
   ipcMain.on(requestCloseChannel, onRequestClose)
   ipcMain.on(popupMenuChannel, onPopupMenu)
+  ipcMain.handle(isMaximizedChannel, onIsMaximized)
 
   ipcMain.on(confirmCloseChannel, onConfirmClose)
   mainWindow.on('closed', () => {
@@ -671,6 +681,7 @@ export function createMainWindow(
     ipcMain.removeListener(maximizeChannel, onMaximize)
     ipcMain.removeListener(requestCloseChannel, onRequestClose)
     ipcMain.removeListener(popupMenuChannel, onPopupMenu)
+    ipcMain.removeHandler(isMaximizedChannel)
     ipcMain.removeListener(confirmCloseChannel, onConfirmClose)
     ipcMain.removeListener(markdownFocusChannel, onMarkdownEditorFocused)
     mainWindow.webContents.removeListener('context-menu', onMainContextMenu)
diff --git a/src/preload/api-types.ts b/src/preload/api-types.ts
index 7899877fc89..4246f84d6ee 100644
--- a/src/preload/api-types.ts
+++ b/src/preload/api-types.ts
@@ -1101,6 +1101,7 @@ export type PreloadApi = {
     onFullscreenChanged: (callback: (isFullScreen: boolean) => void) => () => void
     minimize: () => void
     maximize: () => void
+    isMaximized: () => Promise<boolean>
     onMaximizeChanged: (callback: (isMaximized: boolean) => void) => () => void
     requestClose: () => void
     popupMenu: () => void
diff --git a/src/preload/index.ts b/src/preload/index.ts
index d64636c93c4..c6747eb2abc 100644
--- a/src/preload/index.ts
+++ b/src/preload/index.ts
@@ -1970,6 +1970,10 @@ const api = {
     maximize: (): void => {
       ipcRenderer.send('window:maximize')
     },
+    /** Windows only: read the current maximize state on mount, since
+     *  window:maximize-changed only fires on transitions and a window that
+     *  starts maximized would otherwise show the wrong icon. */
+    isMaximized: (): Promise<boolean> => ipcRenderer.invoke('window:isMaximized'),
     /** Windows only: subscribe to maximize state changes so the renderer-drawn
      *  maximize button can show the correct restore/maximize icon. */
     onMaximizeChanged: (callback: (isMaximized: boolean) => void): (() => void) => {
diff --git a/src/renderer/src/App.tsx b/src/renderer/src/App.tsx
index e38376ed0c9..a534818c3ca 100644
--- a/src/renderer/src/App.tsx
+++ b/src/renderer/src/App.tsx
@@ -64,7 +64,20 @@ const isWindows = !isMac && navigator.userAgent.includes('Windows')
 function WindowControls(): React.JSX.Element {
   const [maximized, setMaximized] = useState(false)
   useEffect(() => {
-    return window.api.ui.onMaximizeChanged(setMaximized)
+    // Why: window:maximize-changed only fires on transitions, so a window
+    // restored to a maximized state at startup would render the wrong icon
+    // until the user first clicks the button. Seed from main on mount.
+    let cancelled = false
+    void window.api.ui.isMaximized().then((value) => {
+      if (!cancelled) {
+        setMaximized(value)
+      }
+    })
+    const unsubscribe = window.api.ui.onMaximizeChanged(setMaximized)
+    return () => {
+      cancelled = true
+      unsubscribe()
+    }
   }, [])
   return (
     <div className="window-controls">
@@ -1091,12 +1104,18 @@ function App(): React.JSX.Element {
                 {workspaceActive && !rightSidebarOpen && (
                   <div
                     className="absolute top-0 z-10 flex items-center h-[36px]"
-                    style={{
-                      right: 'var(--window-controls-width)',
-                      WebkitAppRegion: 'no-drag'
-                    } as React.CSSProperties}
+                    style={
+                      {
+                        right: 'var(--window-controls-width)',
+                        WebkitAppRegion: 'no-drag'
+                      } as React.CSSProperties
+                    }
                   >
                     {rightSidebarToggle}
+                    {/* Why: the fixed-position window-controls overlay (138px,
+                        top-right) sits on top of this floating toggle on Windows.
+                        Reserve its width so the toggle stays clickable. */}
+                    {isWindows && <div className="window-controls-titlebar-spacer" />}
                   </div>
                 )}
                 <div className="flex flex-1 min-w-0 min-h-0 flex-col">
diff --git a/src/renderer/src/assets/main.css b/src/renderer/src/assets/main.css
index d300f2171b5..df47ba9bbd4 100644
--- a/src/renderer/src/assets/main.css
+++ b/src/renderer/src/assets/main.css
@@ -433,7 +433,7 @@
   z-index: 9999;
   display: flex;
   flex-direction: row;
-  height: 42px;
+  height: 36px;
   -webkit-app-region: no-drag;
 }
 
@@ -442,7 +442,7 @@
   align-items: center;
   justify-content: center;
   width: 46px;
-  height: 42px;
+  height: 36px;
   background: transparent;
   border: none;
   color: var(--muted-foreground);
diff --git a/src/renderer/src/components/right-sidebar/index.tsx b/src/renderer/src/components/right-sidebar/index.tsx
index 4182c7578fd..b32894f651a 100644
--- a/src/renderer/src/components/right-sidebar/index.tsx
+++ b/src/renderer/src/components/right-sidebar/index.tsx
@@ -72,6 +72,7 @@ type ActivityBarItem = {
 }
 
 const isMac = navigator.userAgent.includes('Mac')
+const isWindows = !isMac && navigator.userAgent.includes('Windows')
 const mod = isMac ? '\u2318' : 'Ctrl+'
 
 const ACTIVITY_ITEMS: ActivityBarItem[] = [
@@ -305,7 +306,10 @@ function RightSidebarInner(): React.JSX.Element {
               <div className="flex items-center justify-between border-b border-border h-[36px] min-h-[36px] pl-2 pr-1 right-sidebar-header-inset">
                 <TooltipProvider delayDuration={400}>
                   <div className="flex items-center">{activityBarIcons}</div>
-                  {closeButton}
+                  <div className="flex items-center">
+                    {closeButton}
+                    {isWindows && <div className="window-controls-titlebar-spacer" />}
+                  </div>
                 </TooltipProvider>
               </div>
             </ContextMenuTrigger>
@@ -320,7 +324,12 @@ function RightSidebarInner(): React.JSX.Element {
             <span className="text-[11px] font-semibold uppercase tracking-wider text-foreground">
               {visibleItems.find((item) => item.id === effectiveTab)?.title ?? ''}
             </span>
-            <TooltipProvider delayDuration={400}>{closeButton}</TooltipProvider>
+            <TooltipProvider delayDuration={400}>
+              <div className="flex items-center">
+                {closeButton}
+                {isWindows && <div className="window-controls-titlebar-spacer" />}
+              </div>
+            </TooltipProvider>
           </div>
         )}