Add a filter to hide silenced alerts #319
An implementation for the feature request in #313.
Just uses CSS
@matthiasr I initially thought about floating and using that real estate, but then when I added it initially at the bottom I thought it looked fine. If we start having tons of filters we would probably want the two columns (and maybe even show more / show less). I thought it might look weird / lonely to have a second column with a lone checkbox. I can add a screenshot later though.