Using the latest Jenkins version with Cloud Statistics Plugin I noticed that the widget in left panel isn't displayed as good like others : 

I finally discovered that the style is broken in src/main/resources/org/jenkinsci/plugins/cloudstats/WidgetImpl/index.groovy

l.pane(id: "cloudstats", width: 2, title: title, style: "margin-bottom: 20px")

In fact after few investigations, the style option is simply ignored by l.pane method.

Note that I already created the PR : https://github.com/jenkinsci/cloud-stats-plugin/pull/8/files

Vincent