FB21089177: Drop shadow of the Add button on the tab bar is clipped when the toolbar is hidden (macOS 26)

[1024jp]

Starting with macOS 26, control components, such as buttons, in the toolbar and tab bar have large drop shadows.
In some cases, these drop shadows extend beyond the height of their containing bars.
The issue is that the drop shadows can be clipped at the edges of the views that host these controls.
This feedback concerns one such case.

When a window has a tab bar but no toolbar, the drop shadow of the Add (“+”) button in the tab bar is clipped halfway.
This results in a physically incorrect rendering that negatively impacts the visual experience and should be addressed.

Please refer to the attached screenshots for examples.

Steps to Reproduce

In this example, I use TextEdit, but the issue occurs in any application that supports a tab bar and allows the toolbar to be hidden.

1. Open a document-based app capable of hiding its toolbar, such as TextEdit.
2. Create a new document.
3. Choose Format > Make Plain Text to hide the accessory view at the top.
4. Choose View > Hide Toolbar.
5. -> Now observe the Add button in the tab bar. Its drop shadow is clipped at the edge of the tab bar instead of being fully rendered.

Expected Results

The drop shadow of the Add button in the tab bar should render completely, even if it overlaps into the title bar or content view area.

Actual Results

The drop shadow of the Add button in the tab bar does not render into the title bar or content view and is cut off midway.

Environment

• macOS: Version 26.2 Beta 3 (25C5048a)
• Xcode: Version 26.2 beta 2 (17C5038g)

Attachments