$.each(master.calData.eventsPool, function () {
                    if (this.category.length > 0) {
                        this.color = this.category[0].color;
                    }
                });

with this code, this is ok

but before, i was not obliged to add this

this code for example  : https://stachethemes.ticksy.com/?dl=1508082

https://stachethemes.ticksy.com/ticket/1823162/

the code in the txt is not the good one

thx