diff --git a/src/core/editor/Modify.re b/src/core/editor/Modify.re
index ad0f42a2..094739d0 100644
--- a/src/core/editor/Modify.re
+++ b/src/core/editor/Modify.re
@@ -139,10 +139,10 @@ let rec remold = (~fill=Cell.dirty, ctx: Ctx.t): (Cell.t, Ctx.t) => {
               (),
             );
           // hack(?) to avoid completion if no new ghosts are generated. if only
-          // grout are generated, then we can generated them later at the end of
-          // remolding. better to delay their generation bc there may be grout in
-          // the suffix whose relative position around neighboring whitespace we
-          // want to preserve.
+          // grout are generated, then we can generate them later as needed at the
+          // end of remolding. better to delay their generation bc there may already
+          // be grout in the suffix whose relative position around neighboring
+          // whitespace we want to preserve.
           effs
           |> List.for_all(
                fun
diff --git a/src/core/editor/Select.re b/src/core/editor/Select.re
index 915499ac..0b0db8de 100644
--- a/src/core/editor/Select.re
+++ b/src/core/editor/Select.re
@@ -90,7 +90,7 @@ let hstep = (d: Dir.t, z: Zipper.t): option(Zipper.t) => {
     Zipper.mk(~cur=Select(sel), ctx);
   } else {
     // points always grow, only selections can shrink.
-    // d points toward selection anchor.
+    // d points from selection focus toward anchor.
     let sel = Option.get(Cursor.get_select(z.cur));
     let sites = Option.get(Cursor.get_select(cur_site));
     let (_site_foc, site_anc) = Dir.order(sel.focus, sites);
diff --git a/src/core/editor/Zigg.re b/src/core/editor/Zigg.re
index e79bd3bf..5baa196d 100644
--- a/src/core/editor/Zigg.re
+++ b/src/core/editor/Zigg.re
@@ -98,11 +98,7 @@ let of_dn = dn =>
 let of_up = up =>
   Stds.Lists.Framed.ft(up)
   |> Option.map(((up, t: Terr.t)) =>
-       mk(
-         ~up=List.rev(up),
-         Wald.rev(t.wald),
-         ~dn=snd(Slope.Up.unroll(t.cell)),
-       )
+       mk(~up=List.rev(up), t.wald, ~dn=snd(Slope.Dn.unroll(t.cell)))
      );
 
 let roll = (~l=Cell.empty, ~r=Cell.empty, {up, top, dn}: t) =>
@@ -190,6 +186,7 @@ let roll_bounds = (~l=Delim.root, ~r=Delim.root, zigg: Base.t(_)) => {
   let l =
     switch (l) {
     | Root => (List.length(zigg.up), Rel.Neq(Dir.L))
+    | Node(tok) when Token.merges(tok, face(~side=L, zigg)) => (0, Rel.Eq())
     | Node(tok) =>
       switch (push(~side=L, tok, zigg)) {
       | Error(_) => (List.length(zigg.up), Rel.Neq(L))
@@ -207,6 +204,7 @@ let roll_bounds = (~l=Delim.root, ~r=Delim.root, zigg: Base.t(_)) => {
   let r =
     switch (r) {
     | Root => (List.length(zigg.dn), Rel.Neq(Dir.R))
+    | Node(tok) when Token.merges(tok, face(~side=R, zigg)) => (0, Rel.Eq())
     | Node(tok) =>
       switch (push(~side=R, tok, zigg)) {
       | Error(_) => (List.length(zigg.dn), Rel.Neq(R))
diff --git a/src/core/editor/Zipper.re b/src/core/editor/Zipper.re
index beec49ec..0c8a2bb8 100644
--- a/src/core/editor/Zipper.re
+++ b/src/core/editor/Zipper.re
@@ -192,7 +192,13 @@ and unzip_select = (~ctx=Ctx.empty, sel: Path.Selection.t, meld: Meld.t) => {
 };
 
 let unzip_exn = (~ctx=Ctx.empty, c: Cell.t) =>
-  unzip(~ctx, c) |> Options.get_exn(Invalid_argument("Zipper.unzip_exn"));
+  switch (unzip(~ctx, c)) {
+  | Some(z) => z
+  | None =>
+    P.show("unzip_exn ctx", Ctx.show(ctx));
+    P.show("unzip_exn cell", Cell.show(c));
+    raise(Invalid_argument("Zipper.unzip_exn"));
+  };
 
 let rec zip_neighbor = (~side: Dir.t, ~zipped: Cell.t, ctx: Ctx.t) => {
   open Options.Syntax;
diff --git a/src/core/layout/Layout.re b/src/core/layout/Layout.re
index 06adc8b1..0491c782 100644
--- a/src/core/layout/Layout.re
+++ b/src/core/layout/Layout.re
@@ -330,6 +330,50 @@ let states = (~init: State.t, m: LMeld.t) =>
 let nth_line = (tree: LCell.t, r: Loc.Row.t) =>
   Block.nth_line(LCell.flatten(tree), r);
 
+let unroll = (~ctx=Ctx.empty, side: Dir.t, cell: LCell.t) => {
+  let f_open =
+    side == L
+      ? ([], LSlope.Up.unroll(cell)) : (LSlope.Dn.unroll(cell), []);
+  Ctx.map_hd(Frame.Open.cat(f_open), ctx);
+};
+let rec unzip_point =
+        (~side: Dir.t, ~ctx=LCtx.empty, car: Path.Caret.t, c: LCell.t): LCtx.t => {
+  let hd = Path.Caret.hd(car);
+  switch (hd) {
+  | Error(_) =>
+    assert(Option.is_none(c.meld));
+    ctx;
+  | Ok(step) =>
+    let tl = Option.get(Path.Caret.peel(step, car));
+    let m = Options.get_exn(Marks.Invalid, c.meld);
+    switch (LMeld.unzip(step, m)) {
+    | Loop((pre, cell, suf)) =>
+      let ctx = LCtx.add((pre, suf), ctx);
+      unzip_point(~side, ~ctx, tl, cell);
+    | Link((pre, tok, suf)) =>
+      let put_tok_l = () => {
+        let pre = Chain.Affix.cons(tok, pre);
+        let (cell, suf) = Chain.uncons(suf);
+        let ctx = LCtx.add((pre, suf), ctx);
+        unroll(L, cell, ~ctx);
+      };
+      let put_tok_r = () => {
+        let (cell, pre) = Chain.uncons(pre);
+        let suf = Chain.Affix.cons(tok, suf);
+        let ctx = LCtx.add((pre, suf), ctx);
+        unroll(R, cell, ~ctx);
+      };
+      switch (side, tl) {
+      | (L, {path: [char_step, ..._], _}) when char_step >= Block.len(tok) =>
+        put_tok_r()
+      | (L, _) => put_tok_l()
+      | (R, {path: [char_step, ..._], _}) when char_step <= 0 => put_tok_r()
+      | (R, _) => put_tok_l()
+      };
+    };
+  };
+};
+
 let rec unzip = (~ctx=LCtx.empty, cur: Path.Cursor.t, c: LCell.t): LZipper.t => {
   let hd = Path.Cursor.hd(cur);
   switch (hd) {
@@ -342,16 +386,13 @@ let rec unzip = (~ctx=LCtx.empty, cur: Path.Cursor.t, c: LCell.t): LZipper.t =>
   | Ok(step) =>
     let tl = Option.get(Path.Cursor.peel(step, cur));
     let m = Options.get_exn(Marks.Invalid, c.meld);
-    switch (Meld.Base.unzip(step, m)) {
+    switch (LMeld.unzip(step, m)) {
     | Loop((pre, cell, suf)) =>
       let ctx = LCtx.add((pre, suf), ctx);
       unzip(~ctx, tl, cell);
-    // | Link((pre, tok, suf)) =>
-    //   // if caret points to token, then take the entire meld as focused cell
-    //   let cur = Cursor.map(Caret.map(Fun.const()), Fun.id, cur);
-    //   (cur, c, frame);
     | Link((pre, tok, suf)) =>
       switch (cur) {
+      // if caret points to token, then take the entire meld as focused cell
       | Point(_) => LZipper.mk(Cursor.Point(c), ctx)
       | Select(_) =>
         let (l, pre) = Chain.uncons(pre);
@@ -380,8 +421,8 @@ and unzip_select = (~ctx, sel: Path.Selection.t, meld: LMeld.t) => {
     let (hd_pre, tl_pre) = Chain.uncons(pre);
     let l_tl =
       l_hd mod 2 == 0 ? List.tl(l) : LCell.end_path(hd_pre, ~side=R);
-    let z = unzip(Point(Caret.focus(l_tl)), hd_pre);
-    let (eqs, flat) = LCtx.flatten(z.ctx);
+    let ctx = unzip_point(~side=L, Caret.focus(l_tl), hd_pre);
+    let (eqs, flat) = LCtx.flatten(ctx);
     let eqs =
       Chain.Affix.is_empty(tl_pre)
         ? eqs : [(0, (-1)), ...LEqs.incr(~side=L, 1, eqs)];
@@ -397,8 +438,8 @@ and unzip_select = (~ctx, sel: Path.Selection.t, meld: LMeld.t) => {
     let (hd_suf, tl_suf) = Chain.uncons(suf);
     let r_tl =
       r_hd mod 2 == 0 ? List.tl(r) : LCell.end_path(~side=L, hd_suf);
-    let z = unzip(Point(Caret.focus(r_tl)), hd_suf);
-    let (eqs, flat) = LCtx.flatten(z.ctx);
+    let ctx = unzip_point(~side=R, Caret.focus(r_tl), hd_suf);
+    let (eqs, flat) = LCtx.flatten(ctx);
     let eqs =
       Chain.Affix.is_empty(tl_suf)
         ? eqs : [((-1), 0), ...LEqs.incr(~side=R, 1, eqs)];
diff --git a/src/core/structure/Cell.re b/src/core/structure/Cell.re
index 272d7558..5d3ec128 100644
--- a/src/core/structure/Cell.re
+++ b/src/core/structure/Cell.re
@@ -290,10 +290,9 @@ module Space = {
           let shift = 2 * List.length(Meld.tokens(m));
           Marks.map_paths(
             fun
-            | [] => {
-                assert(r.meld == None);
-                [shift];
-              }
+            | [] =>
+              // assert(r.meld == None);
+              [shift]
             | [hd, ...tl] => [hd + shift, ...tl],
           );
         }