I'm not sure what this feature would actually be called but it is a common trait of good code editors vs. plain text editors.
When coding, it is common to have multiple lines with similar code on them.. e.g. HTML:
<input type="button" class="flub" value="Save".../>
<input type="button" class="flub" value="Cancel.../>
foo.bar = "tree";
foo.baz = 57;
The smart code editors track where you navigate to on a line BEFORE you start editing... e.g. in the HTML if I click or arrow my cursor to just before the f" inside the class attribute. If I then type in some new class 'gorf ', then use my down arrow the cursor moves to the "Last Navigation" position from the row above... e.g just inside the class attribute of the next line... vs. what Gomix does right now which is just a literal "same X as the previous line" putting the cursor after the entire class attribute of the next line. It may seem minor but its something that once you've used it in one editor, you can't live without it in any other editor.