fix: incorrect view ordering for customButtonsOnHover (#15564)

atom/browser/api/atom_api_browser_window_mac.mm

@@ -62,7 +62,12 @@ void BrowserWindow::OverrideNSWindowContentView(InspectableWebContents* iwc) {
   NSView* webView = iwc->GetView()->GetNativeView();
   NSView* contentView = [window()->GetNativeWindow() contentView];
   [webView setFrame:[contentView bounds]];
-  [contentView addSubview:webView];
+
+  // ensure that buttons view is floated to top of view hierarchy
+  NSArray* subviews = [contentView subviews];
+  NSView* last = subviews.lastObject;
+  [contentView addSubview:webView positioned:NSWindowBelow relativeTo:last];
+
   [contentView viewDidMoveToWindow];
 }
 

atom/browser/native_window_mac.mm

@@ -76,9 +76,6 @@
   NSButton* miniaturize_button =
       [NSWindow standardWindowButton:NSWindowMiniaturizeButton
                         forStyleMask:NSWindowStyleMaskTitled];
-  NSButton* zoom_button =
-      [NSWindow standardWindowButton:NSWindowZoomButton
-                        forStyleMask:NSWindowStyleMaskTitled];
 
   CGFloat x = 0;
   const CGFloat space_between = 20;
@@ -91,11 +88,7 @@
   x += space_between;
   [self addSubview:miniaturize_button];
 
-  [zoom_button setFrameOrigin:NSMakePoint(x, 0)];
-  x += space_between;
-  [self addSubview:zoom_button];
-
-  const auto last_button_frame = zoom_button.frame;
+  const auto last_button_frame = miniaturize_button.frame;
   [self setFrameSize:NSMakeSize(last_button_frame.origin.x +
                                     last_button_frame.size.width,
                                 last_button_frame.size.height)];
@@ -1412,6 +1405,8 @@ void NativeWindowMac::AddContentViewLayers() {
     if (title_bar_style_ == CUSTOM_BUTTONS_ON_HOVER) {
       buttons_view_.reset(
           [[CustomWindowButtonView alloc] initWithFrame:NSZeroRect]);
+      // NSWindowStyleMaskFullSizeContentView does not work with zoom button
+      SetFullScreenable(false);
       [[window_ contentView] addSubview:buttons_view_];
     } else {
       if (title_bar_style_ != NORMAL)

docs/api/browser-window.md

@@ -222,11 +222,11 @@ It creates a new `BrowserWindow` with native properties as set by the `options`.
       the top left.
     * `hiddenInset` - Results in a hidden title bar with an alternative look
       where the traffic light buttons are slightly more inset from the window edge.
-    * `customButtonsOnHover` Boolean (optional) - Draw custom close, minimize,
-      and full screen buttons on macOS frameless windows. These buttons will not
-      display unless hovered over in the top left of the window. These custom
-      buttons prevent issues with mouse events that occur with the standard
-      window toolbar buttons. **Note:** This option is currently experimental.
+    * `customButtonsOnHover` Boolean (optional) - Draw custom close,
+      and minimize buttons on macOS frameless windows. These buttons will not display
+      unless hovered over in the top left of the window. These custom buttons prevent
+      issues with mouse events that occur with the standard window toolbar buttons.
+      **Note:** This option is currently experimental.
   * `fullscreenWindowTitle` Boolean (optional) - Shows the title in the
     title bar in full screen mode on macOS for all `titleBarStyle` options.
     Default is `false`.

docs/api/frameless-window.md

@@ -49,10 +49,12 @@ win.show()
 
 #### `customButtonsOnHover`
 
-Uses custom drawn close, miniaturize, and fullscreen buttons that display
-when hovering in the top left of the window. These custom buttons prevent issues
-with mouse events that occur with the standard window toolbar buttons. This
-option is only applicable for frameless windows.
+Uses custom drawn close, and miniaturize buttons that display
+when hovering in the top left of the window. The fullscreen button
+is not available due to restrictions of frameless windows as they
+interface with Apple's MacOS window masks. These custom buttons prevent
+issues with mouse events that occur with the standard window toolbar buttons.
+This option is only applicable for frameless windows.
 
 ```javascript
 const { BrowserWindow } = require('electron')