diff --git a/crates/edit/src/tests.rs b/crates/edit/src/tests.rs
index 692a21c8c2..ecac4c782c 100644
--- a/crates/edit/src/tests.rs
+++ b/crates/edit/src/tests.rs
@@ -6709,3 +6709,36 @@ fn added_text_paragraphs_keep_their_own_alignments() {
     let tidy = paragraph_align::tidy(vec![Some(Align::Left), Some(Align::Right)], Align::Left);
     assert_eq!(tidy, [None, Some(Align::Right)]);
 }
+
+/// A one-row title over a body column: an alignment picked for it is measured across the column.
+/// Left puts it on the column's left edge, and centring it again leaves it where it is, rather
+/// than aligning it in its own box (a no-op) or toward the page's margin (moving it right each
+/// time). It is aligned as the editor aligns a selected row, in whichever paragraph holds it.
+#[test]
+fn a_lone_row_aligns_across_the_column_it_sits_in() {
+    let mut doc = text_page(
+        "BT /F1 24 Tf 1 0 0 1 250 700 Tm (Title) Tj ET          BT /F1 10 Tf 12 TL 72 650 Td (The body of the page runs across the whole column here.) Tj T* (It has a second row that is a little shorter.) Tj ET",
+    );
+    let blocks = text::text_blocks(&doc, 0).unwrap();
+    assert_eq!(blocks[0].text, "Title");
+    let column = [blocks[1].rect[0], blocks[1].rect[2]];
+    let title = |doc: &Document| text::text_lines(doc, 0).unwrap().into_iter().find(|l| l.text == "Title").unwrap().rect;
+    let align = |doc: &mut Document, a: added::Align| {
+        let lines = text::text_lines(doc, 0).unwrap();
+        let line = lines.iter().position(|l| l.text == "Title").unwrap();
+        let blocks = text::text_blocks(doc, 0).unwrap();
+        let (index, block) = blocks.iter().enumerate().find(|(_, b)| b.lines.contains(&line)).unwrap();
+        // The title is the paragraph's first row.
+        let style = text::BlockStyle { aligns: vec![Some(a)], ..Default::default() };
+        text::rewrite_block(doc, 0, index, Some(&block.editor_text), &style).unwrap();
+    };
+    align(&mut doc, added::Align::Center);
+    let centred = title(&doc);
+    assert!(((centred[0] + centred[2]) / 2.0 - (column[0] + column[1]) / 2.0).abs() < 1.0, "centred in the column: {centred:?} vs {column:?}");
+    align(&mut doc, added::Align::Center);
+    assert!((title(&doc)[0] - centred[0]).abs() < 0.5, "centring again leaves it where it is: {:?} vs {centred:?}", title(&doc));
+    align(&mut doc, added::Align::Left);
+    assert!((title(&doc)[0] - column[0]).abs() < 0.5, "left: back on the column's edge, {:?} vs {column:?}", title(&doc));
+    align(&mut doc, added::Align::Right);
+    assert!((title(&doc)[2] - column[1]).abs() < 1.0, "right: on the column's right edge, {:?} vs {column:?}", title(&doc));
+}
diff --git a/crates/edit/src/text.rs b/crates/edit/src/text.rs
index 3ce185a985..e8e80d29f5 100644
--- a/crates/edit/src/text.rs
+++ b/crates/edit/src/text.rs
@@ -24,7 +24,7 @@ use crate::EditError;
 mod regions;
 #[path = "text_session.rs"]
 mod session;
-use regions::{group_blocks, is_centred, rewrite_styled_block};
+use regions::{alignment_frame, group_blocks, is_centred, rewrite_styled_block};
 pub use session::TextSession;
 
 /// One line of existing text.
@@ -2678,6 +2678,16 @@ fn rewrite_block_from(
 ) -> Result<LineEdit, EditError> {
     let blocks = group_blocks(&lines);
     let b = blocks.get(block).cloned().ok_or_else(|| EditError::Invalid(format!("page {} has no paragraph {}", page + 1, block + 1)))?;
+    // An alignment for a one-row paragraph is laid out across the column it sits in, as a
+    // paragraph of that width moved to its left edge.
+    let framed;
+    let style = match alignment_frame(&lines, &b, style) {
+        Some([left, right]) => {
+            framed = BlockStyle { width: Some(right - left), offset: Some([left - b.rect[0], 0.0]), ..style.clone() };
+            &framed
+        }
+        None => style,
+    };
     let members: Vec<&TextLine> = b.lines.iter().map(|i| &lines[*i]).collect();
     // One clipping run is enough: rewriting the paragraph would drop its mask with the rest.
     let mut dropped = coincident_ops(&lines, &members);
diff --git a/crates/edit/src/text_regions.rs b/crates/edit/src/text_regions.rs
index 11ae6c5a2c..d9465cdffd 100644
--- a/crates/edit/src/text_regions.rs
+++ b/crates/edit/src/text_regions.rs
@@ -44,6 +44,31 @@ fn neighbour_left(lines: &[TextLine], block: &TextBlock) -> Option<f64> {
     Some(best as f64 / 4.0)
 }
 
+/// Where an alignment picked for a one-row paragraph is measured, as `[left, right]`: the column of
+/// text it sits in (the left edge the rest of the page's text uses, to the furthest right those
+/// rows reach) when that column holds it, otherwise its own box. A lone row's own box is no frame
+/// to align in: left-aligning a title centred on the page left it where it was, and since a single
+/// row grows to the page's margin, centring it again moved it right each time. `None` when no
+/// alignment is asked for, or when the paragraph is several rows, turned, or given a width or a
+/// move of its own.
+pub(super) fn alignment_frame(lines: &[TextLine], block: &TextBlock, style: &BlockStyle) -> Option<[f64; 2]> {
+    let asked = style.align.is_some() || style.aligns.iter().any(Option::is_some);
+    if !asked || style.width.is_some() || style.offset.is_some() || block.rows.len() != 1 || block.rotation.abs() > 0.01 {
+        return None;
+    }
+    let own = [block.rect[0], block.rect[2]];
+    let tolerance = block.size.max(1.0) * 0.5;
+    let Some(left) = neighbour_left(lines, block) else { return Some(own) };
+    let right = lines
+        .iter()
+        .enumerate()
+        .filter(|(i, line)| !block.lines.contains(i) && (line.rect[0] - left).abs() < tolerance)
+        .map(|(_, line)| line.rect[2])
+        .fold(f64::NEG_INFINITY, f64::max);
+    let holds = right.is_finite() && right - left > own[1] - own[0] && own[0] >= left - tolerance && own[1] <= right + tolerance;
+    Some(if holds { [left, right] } else { own })
+}
+
 /// Whether a block reads as centred, and so must keep its centre when it grows or wraps.
 ///
 /// Several ragged rows whose left edges disagree while their centres agree are centred. A one row