In IE8 but not Firefox, scrolling the browser window instead of just the scroll bar within the dhtmlXScheduler control is resulting in dhtmlXScheduler resolving click coordinates incorrectly. For example, I scroll to the bottom of the calendar and double click to create a new event, but in IE8 this is causing the new event to be created several hundred pixels higher in the calendar.

Problem was confirmed and fixed, fix will be included in the next release
If you need the fix ASAP - you can try to use attached patch ( just add it after default code )
patch.zip (619 Bytes)