Hide nonexistent combinations when filtering metrics on dashboard

[KalleOlaviNiemitalo]

When I filter metrics on the dashboard, I'd like the UI to indicate which other filters I can add without excluding all measurements.

For example, let's say a service outputs metrics with these tag combinations:

• server=koraktor, sensor=cpu
• server=koraktor, sensor=memory
• server=grail, sensor=cpu
• server=grail, sensor=power_supply

Then if I set a filter on "sensor=memory" and click the "server" filter button, I'd like the dashboard to show that only "server=koraktor" has measurements available.

Something like in xfontsel.

[adamint]

@KalleOlaviNiemitalo would you be able to give a reproduction in-code in the Stress App? Apologies.