Symptom:
When your mouse cursor over the maximize/minimize button of the VSCode window there’s no Snap Layout balloon shown.

Solution 1:
Press Win + Z; It’s the window shortcut to open the snap layout menu.
Solution 2:
Modify vscode user settings. The settings.json file.
- Use command pallete; press
Ctrl+Shift+p(Window OS) orCommand+Shift+p(macOS) - type settings (after > symbol) then select
Preferences: Open Settings (JSON)

- insert this key:value into the file
"window.titleBarStyle": "native" - Save the modification
- Now when mouse over the maximize button the snap layout balloon should be appeared