Conditional filtering based on specific row value, with several dashboards

HI vannipart,

>>Creating special table for "all" is one option, but it isn't solving my problem if nothing is selected. 

Measure can do some specific operation to deal with 'all' item selected, but it can't as the group column of visual. For your scenario, you can try to add total row in power query.

Query:

Custom1 = Table.InsertRows(#"Previous Step",Table.RowCount(#"Previous Step"),{[ColumnName1="ALL",ColumnName2=List.Sum(#"Previous Step"[ColumnName2])]})

Sample:

Custom1 = Table.InsertRows(#"Removed Columns",Table.RowCount(#"Removed Columns"),{[country="ALL",unit=List.Sum(#"Removed Columns"[unit])]})

For query:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("XZFNcoMwDIXv4nUWRjLGLB2wW1pCmBhCJgz3v0Yl2emk3QB+3/PTD/uu4jCpk3LQWDQtfaU5dIMf1XHaVR9WUhA1GrTwH14vAonRuxMt3jxrJmupj0nk7jPQETTrzghJvZCP840JQvaLtiYOqa0huYLsFpA2iUEEVvsUg8hfM09QgSO/0ezvMpg4p2lrMAiu5iZLhXMYc1V6hpIyXbkTg+QGy4sIfQb99F2qItRO2nnlPH18y0nZH9LCQbVBbFjfSgG/LjmH+wdGrxvj+uCt5Rz/qts9edrKNKTrPySkmf0t35AgIj4PJvu3TvNGwb6jOfB8lW4JuJK2ZTQsXn4PMKoKyyjdebc1VoRKJdEv4fE7uQ9RHccP", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [country = _t, unit = _t, Column1 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"country", type text}, {"unit", Int64.Type}, {"Column1", type text}}),
    #"Removed Columns" = Table.RemoveColumns(#"Changed Type",{"Column1"}),
    Custom1 = Table.InsertRows(#"Removed Columns",Table.RowCount(#"Removed Columns"),{[country="ALL",unit=List.Sum(#"Removed Columns"[unit])]})
in
    Custom1

Regards,

Xiaoxin Sheng