Problem

When using Confluence Team Calendars in the Denver (UTC‑7) timezone, clicking on a date in the month view opens the "Create event" dialog with the previous day's date pre‑filled.

Environment

• Confluence Cloud (Team Calendars)

• Affected users' browser/OS timezone: America/Denver (UTC‑7, getTimezoneOffset() = 420)

Steps to Reproduce

1. Set OS/browser timezone to America/Denver (UTC‑7).

1. Open the calendar in month view.

1. Click on any date, e.g. 21 November 2025.

Expected Results

The "Create event" dialog opens with the selected date (e.g. 21 Nov 2025) pre‑filled as the event date.

Actual Results

The "Create event" dialog opens with the previous day (e.g. 20 Nov 2025) pre‑filled as the event date, i.e. the date is shifted one day earlier than the date clicked in the calendar.

Workaround

Manually updating the correct date in the 'Create Event' dialog window

Notes

Only tested with Denver, this may affect other negative timezones.