I write a form, and I noticed that as I moved with the keyboard (Shift+down) or (Shift+up) inside the form, the bookmarks can also selected the lines a faint. Thank God when deleted in text form, the bookmarks are not erased it. Quite frustrating.
That is a known issue in all OS.
It is annoying but not evil enough (be lucky!) to kill our bookmarks.
It may be fixed in a next Snapshot, i hope.