Dashboard Variable - Press x on filter variable with value ALL produce empty result

[marcoberri]

Is your feature request related to a problem?

If I click on x value when "ALL" is selected, the widget with graph reload visualization without show values. My Variable is set to IN {{.environment}}

Describe the solution you'd like

Is possible remove the (x) where the value is ALL?

Or in alternative force the default value always to ALL?

thx