The bottom button bar overlaps with the header when the sidepanel is long.
To produce

• Setup Jenkins with an agent with a few executors.
• create a new view.
• create a matrix project with a large matrix that will start about 250 builds. As build step run system groovy with a sleep of 30sec
• run the matrix project -> a long queue is there
• with this queue click on "Edit View"
• scroll down -> the bottom button bar with "Save" / "Apply" is seen over the header

Copy from https://github.com/jenkinsci/customizable-header-plugin/issues/246