The plugin "Column Ruler" has two bugs (latest version of Column Ruler and jedit 4.5 pre1):
1. Add Marker/Guide through the "Plugins Options" dialog doesn't work most of time. After input the marker the list doesn't have that marker. Sometimes works though.
2. The guide line created through column ruler doesn't show up when jEdit starts. I have to always click on the ruler at the column number and the guide line is shown. It's tedious to do it every time.