The issue you're running into is that quick filters can only control the data source they are created on.
A workaround you can currently use in Tableau in this situation with wanting single-select filters to cross data sources is to employ a parameter + calculated field combination. This works because parameters persist through an entire workbook, beyond quick filters. I believe Tableau 8 is also going to introduce some additional options.
1) Create Nivel and Grado parameters with the choices that would be available from the Nivel and Grado dimensions in both sources
2) Create a calculated field for each parameter in each data source (4 in all) as:
IF [Escoge Grado] = [GRADO]
3) Add the field to the filter shelf and set to be Global (if you want the parameter to control all views from that source)
Looking at your data, it doesn't appear that you have ANY data points which have "Diversificado" on the map-source, and you don't have any data points for a Grado other than 0 on the line-source. Is that what you meant by "not all records available on the data source for the line graphs are available on the map and quick filters data source?"
Resultados de Aprendizaje.twbx.zip 306.4 KB
Thanks for your answer Mark, I will try the solution you propose.
The map-source has data points which have "Primaria" and "Diversificado" on NIVEL and values 1, 2 and 3 on Grado. This values also exist on the line-source.
However other values only exist on the line-source, like "Básicos" on NIVEL.
Do you think this would afect in some way my dashboard?