Remove one filter in a measure

Hi all,

I have a chart like this:

On every string, there are one or more events. I can click on this chart - both to choose whole string or a single event. I would like to have a measure that will tell me how many events are there on a string, regardless if I click a whole string or a single event. For example, on string 1 I would expect the value to be 6.

I thought it could be like:

_howManyCleanings = CALCULATE(
COUNT(TableData[EventID]),
REMOVEFILTERS(TableData[StringID])
)

but this is not working - when I click string 1 it shows correctly value 6, but if I click on the event, the measure shows 1, instead of still 6.

How to fix this?

Thanks,

Joanna