ALLSELECTED Removes context filters from columns and rows in the current query, while retaining all other context filters or explicit filters.
The ALLSELECTED function gets the context that represents all rows and columns in the query, while keeping explicit filters and contexts other than row and column filters. This function can be used to obtain visual totals in queries.
Syntax
ALLSELECTED([tableName | columnName[, columnName[, columnName[,…]]]] )
Parameters
TableName – The name of an existing table, using standard DAX syntax. This parameter cannot be an expression. This parameter is optional.
ColumnName – The name of an existing column using standard DAX syntax, usually fully qualified. It cannot be an expression. This parameter is optional.
Return Value
The context of the query without any column and row filters.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference