How does Looker Studio interpret fields w/ same name, in different sources, when applying a filter?

[HugoTorres]

I am building a dashboard and I have noticed that despite the fact the I have visualizations from two different data sources, a filter for a field on data source A also filters the visualization from data source B, using a column with the same name. However, when I tried to do this with a calculated field, despite haviong the same name, the same behavior was not verified. How does Looker Studio establish these relationships? Is it for data fields only and not for calculated fields? Is these any way to explicitly establish these connections?

[lauratilton]

The two fields need to have the same Field ID in order to work the way you are describing. When they have the same name and are from two different data sources, they often have the same Field ID, even though you don't see it. If you create a calculated field in one source, you can create your own Field ID, and then use the same field ID in your other source for another calculated field. Those two fields that have the same Field ID should work as you describe. (Note that once a field is created, its Field ID can't be changed.)

Here's a great video that explains it well.