Hello,
I have today used the beforeEventSelectionChange listener on the scheduler. However I experienced some issues with seeing the deselected events from the provided event data.
Whenever I deselect anything, the deselected array is empty..
and when I have something selected and select something else, the deselected array contains the same events as the selected array..
The eventSelectionChange event provides the correct selection, selected and deselected though. But for what I had planned to design I need access to the beforeEventSelectionChange so that I may change the selection in some cases than what is the default expected..
This issue is very easy to reproduce in one of your examples:
https://www.bryntum.com/products/schedulerpro/examples-scheduler/dragselection/
and adding the following code at the end:
scheduler.addListener({
thisObj: this,
beforeEventSelectionChange: (event) => console.log(event)
});