[Calendar] onEventResize returns incorrect args.newStart with heightSpec="BusinessHoursNoScroll" since v4.2.1

Hi Dan,

Following up on my previous reports (#6666, #6724), I wanted to first thank you for the RTL fix in v4.8.0 -- using the rtl: true config property resolves the reversed day selection issue I reported.

However, I've found that the args.newStart value returned during an onEventResize operation contains an incorrect time with a significant offset from the actual drag position when heightSpec is set to "BusinessHoursNoScroll". This appears to have been introduced in v4.2.1 -- likely as a side effect of the BusinessHoursNoScroll fix for onTimeRangeSelected that was included in that same release.

Versions tested:

VersiononEventResize with BusinessHoursNoScroll

3.32.1

Working correctly

3.33.0

Working correctly

4.2.0

Working correctly

4.2.1

Broken (regression introduced)

4.8.0

Broken

5.4.1

Broken

5.5.0

Broken

Environment:

• @daypilot/daypilot-lite-react (React wrapper)

• heightSpec: "BusinessHoursNoScroll"

• businessBeginsHour: 6, businessEndsHour: 23

• cellHeight: 30

• Tested in both LTR and RTL -- the bug is not direction-specific

Steps to reproduce:

1. Create a Calendar with heightSpec: "BusinessHoursNoScroll", businessBeginsHour: 6, businessEndsHour: 23

2. Add an event starting at 10:00 and ending at 12:30

3. Drag the top edge of the event upward to resize the start time 30 minutes earlier

Expected behavior: args.newStart = 2026-04-16T09:30:00

Actual behavior: args.newStart = 2026-04-16T15:30:00 (a +6 hour offset from the expected value)

Console evidence:

{

originalStart: '2026-04-16T10:00:00',

originalEnd: '2026-04-16T12:30:00',

newStart: '2026-04-16T15:30:00', // Expected: 09:30, got 15:30

newEnd: '2026-04-16T12:30:00'

}

Since the start time (15:30) ends up after the end time (12:30), the event becomes invalid and effectively disappears from the calendar.

The onTimeRangeSelected handler works correctly in all tested versions -- only onEventResize seems to be affected, and only from v4.2.1 onwards.

So for the time being I’m still soft locked into version 3.32.1 which has both RTL and onEventResize functionalities in working order.

If you require any additional configuration specifics from my set up, just let me know.

Thank you!