Show calendar on chart (for specific currency)
On the Toolbox click on "Calendar", right click or double click anywhere inside the toolbox, from the pop up context menu, you would see Priority, Currency and Country.
I wish that it would work ;)
But unfortunately, it looks like this after filtering the events in the list (then selecting 'Delete All Events' and 'Add All Events' - generally speaking, it does what it says: Adding ALL events ;)

And even if you just want to set your preferred countries, etc. to have at least the list with interesting events below the chart, after a MT-restart you can redo your selection because MT resets your selection. That's the reason why the Calendar-tab in my MT5 is always closed since a blong time (but today was a good opportunity to check if there has anything changed, but it hasn't ;)