Bug: Double confirmation alert when closing a note tab

[camiicode]

Problem:
When closing a note tab using the middle mouse button,
the browser displays the native confirmation alert twice,
requiring the user to confirm the action two times.

This creates friction and a confusing user experience.

Expected behavior:
The confirmation alert should appear only once
when closing a note tab.

Possible cause:
The close handler is being triggered more than once
(e.g. both onmousedown and onclick, or duplicated listeners).

Steps to reproduce:

1. Open multiple note tabs.
2. Click the middle mouse button on a tab to close it.
3. Observe that the confirmation alert appears twice.

Acceptance criteria:

• Only one confirmation alert is shown.
• Tab closes correctly after a single confirmation.
• Behavior is consistent across input methods (mouse / touch).