Bug Description
When macOS Language & Region is set to use the Buddhist calendar (Thai Buddhist Era / พ.ศ.), Itsycal displays the correct date number but maps it to the wrong day of the week, shifted by approximately 2 days.
Steps to Reproduce
- Go to macOS System Settings → General → Language & Region
- Set Calendar to Buddhist
- Open Itsycal
- Observe that dates are placed under incorrect weekday columns
Expected Behavior
- April 5, 2026 (2569 พ.ศ.) should appear under Saturday
- All dates should align correctly with their weekday columns
Actual Behavior
- April 4 appears under Tuesday instead of Saturday
- Dates are shifted roughly 2 columns from the correct weekday
Root Cause (suspected)
Itsycal appears to use the Buddhist year number (e.g. 2569) directly for day-of-week calculation without first converting it to the Gregorian year (2026). This causes the weekday mapping to be off.
Environment
- macOS: Sequoia
- Itsycal: latest version
- Language & Region → Calendar: Buddhist
- Locale: Thailand (th_TH)
Workaround
Changing the calendar back to Gregorian in System Settings resolves the issue. However, users who prefer to see พ.ศ. year display are affected.
Bug Description
When macOS Language & Region is set to use the Buddhist calendar (Thai Buddhist Era / พ.ศ.), Itsycal displays the correct date number but maps it to the wrong day of the week, shifted by approximately 2 days.
Steps to Reproduce
Expected Behavior
Actual Behavior
Root Cause (suspected)
Itsycal appears to use the Buddhist year number (e.g. 2569) directly for day-of-week calculation without first converting it to the Gregorian year (2026). This causes the weekday mapping to be off.
Environment
Workaround
Changing the calendar back to Gregorian in System Settings resolves the issue. However, users who prefer to see พ.ศ. year display are affected.