diff --git a/crates/edit/src/bin/edit/documents.rs b/crates/edit/src/bin/edit/documents.rs
index 6596bb1ab0d..1bbdde61afd 100644
--- a/crates/edit/src/bin/edit/documents.rs
+++ b/crates/edit/src/bin/edit/documents.rs
@@ -282,6 +282,7 @@ impl DocumentManager {
         let buffer = TextBuffer::new_rc(false)?;
         {
             let mut tb = buffer.borrow_mut();
+            tb.set_insert_final_newline(!cfg!(windows)); // As mandated by POSIX.
             tb.set_margin_enabled(true);
             tb.set_line_highlight_enabled(true);
         }
diff --git a/crates/edit/src/buffer/mod.rs b/crates/edit/src/buffer/mod.rs
index e51c01e5929..9277192e500 100644
--- a/crates/edit/src/buffer/mod.rs
+++ b/crates/edit/src/buffer/mod.rs
@@ -316,7 +316,7 @@ impl TextBuffer {
             ruler: 0,
             encoding: "UTF-8",
             newlines_are_crlf: cfg!(windows), // Windows users want CRLF
-            insert_final_newline: !cfg!(windows), // As mandated by POSIX.
+            insert_final_newline: false, // NOTE: Even with POSIX, single-line buffers need this to be false
             overtype: false,
 
             wants_cursor_visibility: false,