Crash on Window Close with Tkinter Integration

[cdaraio]

I am encountering a crash when closing a pywebview window in an application that integrates both Tkinter and webview on macOS. The issue arises when the user closes the webview window, causing the entire application to crash. After investigating the code, I believe this might be related to how the Tkinter and webview event loops interact on macOS, especially given that webview uses AppKit and NSApplication while Tkinter runs its own event loop. Any suggestions or fixes would be appreciated.