**Kibana version:** master **Elasticsearch version:** master **Describe the bug:** The charts show a pink background even though a threshold hasn't been set. **Steps to reproduce:** 1. Go to central alerts management 1. Create "Metric threshold" alert 1. "SELECT A FIELD" and set to `system.cpu.user.pct` 1. You should see something that looks like the screen shot below **Expected behavior:** Thresholds shouldn't appear to the threshold value is set. **Screenshots (if relevant):** 
Kibana version:
master
Elasticsearch version:
master
Describe the bug:
The charts show a pink background even though a threshold hasn't been set.
Steps to reproduce:
system.cpu.user.pctExpected behavior:
Thresholds shouldn't appear to the threshold value is set.
Screenshots (if relevant):