Datepicker: beforeShowDay is passed wrong date when dayNamesShort are used

[pramodjodhani]

👋

I had raised a similar issue previously #1971, which was for "D M d yy" format. I have found that the same problem happens with dd. MM yy format too.

Please check this minimal example to recreate the problem.: https://jsfiddle.net/smnt1o5r/2/

Please note that the dates passed to the callback function are of 2031, which is very random

I also noticed that this time the problem is not dependent on dayNamesShort

[mgol]

Thanks for the report. Since the issue is already in 1.12, given limited team resources it's not likely to be fixed by the UI team; see the project status at https://blog.jqueryui.com/2021/10/jquery-maintainers-update-and-transition-jquery-ui-as-part-of-overall-modernization-efforts/. PRs are welcome if they're not too complex and contain tests.