To bookmark lines within a file, click on the gutter / blank space in the first column of the line. This should create a bookmark icon  

for that line and add the line in the “Line Marks” tab in the sidebar. 

 

To remove a line mark you can click on the bookmark icon in that line to toggle it off. Alternative, from the Line Marks view in the sidebar 

select the line mark (Cmd-click to multi-select) and then either press Delete key or click on the        icon. 

 

To filter line marks by keywords, use the search field to enter the matching text. Only line marks that have a line with that text will be then displayed.  

 

Double-click on the bookmarked line to jump to that line in the file.  

 

Make sure to Bookmark the file itself to retain the line marks in the file for later access - Only bookmarked files will persist the line marks