Thanks P Brady for the help but when I used it, the Events key title was still visible so I replace the css codes with these two lines of CSS in the settings of my theme:
.block_calendar_month.block .filters.calendar_filters
{display:none;}
.block_calendar_month.block .eventskey {display:none;}
Afterwards, every element of Events key on my calendar block as removed. I hope this helps someone else aswell.