diff --git a/cmd/qrunproxy/static/index.html b/cmd/qrunproxy/static/index.html
index 769c282..63f134f 100644
--- a/cmd/qrunproxy/static/index.html
+++ b/cmd/qrunproxy/static/index.html
@@ -164,7 +164,10 @@ function render(data) {
     `<span><span class="status-dot"></span>QLab Connected</span>`;
 
   const timeline = document.getElementById('timeline');
-  timeline.style.gridTemplateColumns = `repeat(${data.tracks.length}, 140px)`;
+  const numTracks = data.tracks.length;
+  const numRows = Math.max(...data.tracks.map(t => t.cells.length));
+  timeline.style.gridTemplateColumns = `repeat(${numTracks}, 140px)`;
+
   data.tracks.forEach(track => {
     const el = document.createElement('div');
     el.className = 'track-header';
@@ -172,12 +175,13 @@ function render(data) {
     timeline.appendChild(el);
   });
 
-  data.rows.forEach((row, rowIndex) => {
-    const hasCue = row.cells.some(c => c.block_id && c.event && (data.blocks[c.block_id] || {}).type === 'cue');
-    const hasSignal = !hasCue && row.cells.some(c => c.event && c.is_signal);
+  for (let r = 0; r < numRows; r++) {
+    const cells = data.tracks.map(t => t.cells[r] || {});
+    const hasCue = cells.some(c => c.block_id && c.event && (data.blocks[c.block_id] || {}).type === 'cue');
+    const hasSignal = !hasCue && cells.some(c => c.event && c.is_signal);
     const rowCls = hasCue ? ' cue-row' : (hasSignal ? ' sig-row' : '');
 
-    row.cells.forEach(c => {
+    cells.forEach(c => {
       const div = document.createElement('div');
       div.className = 'cell' + rowCls;
       if (c.is_title) {
@@ -185,7 +189,7 @@ function render(data) {
         div.innerHTML = `<div class="block block-mid ${block.type || ''}"><div class="title">${block.name || ''}</div></div>`;
       } else if (c.block_id) {
         const block = data.blocks[c.block_id] || {};
-        const isInfinity = rowIndex === data.rows.length - 1 && !c.is_end && !c.is_title;
+        const isInfinity = r === numRows - 1 && !c.is_end && !c.is_title;
         let seg = 'mid';
         if (c.is_start && c.is_end) seg = 'single';
         else if (c.is_start) seg = 'start';
@@ -206,7 +210,7 @@ function render(data) {
       }
       timeline.appendChild(div);
     });
-  });
+  }
 }
 </script>
 </body>
diff --git a/cmd/qrunproxy/timeline.go b/cmd/qrunproxy/timeline.go
index 5e1cc4c..a2f5835 100644
--- a/cmd/qrunproxy/timeline.go
+++ b/cmd/qrunproxy/timeline.go
@@ -40,14 +40,14 @@ type TriggerTarget struct {
 	Hook  string `json:"hook"`
 }
 
-type Timeline struct {
-	Tracks []Track          `json:"tracks"`
-	Blocks map[string]Block `json:"blocks"`
-	Rows   []TimelineRow    `json:"rows"`
+type TimelineTrack struct {
+	Track
+	Cells []TimelineCell `json:"cells"`
 }
 
-type TimelineRow struct {
-	Cells []TimelineCell `json:"cells"`
+type Timeline struct {
+	Tracks []TimelineTrack `json:"tracks"`
+	Blocks map[string]Block `json:"blocks"`
 }
 
 type TimelineCell struct {
@@ -150,10 +150,14 @@ func BuildTimeline(show Show) (Timeline, error) {
 	b.assignRows()
 	b.collapseEmptyRows()
 
+	tracks := make([]TimelineTrack, len(b.tracks))
+	for i, t := range b.tracks {
+		tracks[i] = TimelineTrack{Track: t, Cells: b.trackCells[i]}
+	}
+
 	return Timeline{
-		Tracks: b.tracks,
+		Tracks: tracks,
 		Blocks: b.blocks,
-		Rows:   b.renderRows(),
 	}, nil
 }
 
@@ -340,10 +344,22 @@ func (b *timelineBuilder) insertGap(track, beforeIndex int) {
 		}
 	}
 
+	gap := TimelineCell{IsGap: true}
+	for i := beforeIndex - 1; i >= 0; i-- {
+		c := b.trackCells[track][i]
+		if c.IsGap {
+			continue
+		}
+		if c.BlockID != "" && !c.IsEnd {
+			gap.BlockID = c.BlockID
+		}
+		break
+	}
+
 	cells := b.trackCells[track]
 	newCells := make([]TimelineCell, 0, len(cells)+1)
 	newCells = append(newCells, cells[:beforeIndex]...)
-	newCells = append(newCells, TimelineCell{IsGap: true})
+	newCells = append(newCells, gap)
 	newCells = append(newCells, cells[beforeIndex:]...)
 	b.trackCells[track] = newCells
 
@@ -435,41 +451,3 @@ func (b *timelineBuilder) collapseEmptyRows() {
 	}
 }
 
-func (b *timelineBuilder) renderRows() []TimelineRow {
-	maxLen := 0
-	for _, cells := range b.trackCells {
-		if len(cells) > maxLen {
-			maxLen = len(cells)
-		}
-	}
-
-	rows := make([]TimelineRow, maxLen)
-	for r := range rows {
-		rows[r].Cells = make([]TimelineCell, len(b.tracks))
-	}
-
-	for trackIdx, cells := range b.trackCells {
-		activeBlock := ""
-		for r := 0; r < maxLen; r++ {
-			if r < len(cells) {
-				c := cells[r]
-				if c.IsGap {
-					if activeBlock != "" {
-						rows[r].Cells[trackIdx] = TimelineCell{BlockID: activeBlock}
-					}
-				} else {
-					rows[r].Cells[trackIdx] = c
-					if c.BlockID != "" && !c.IsEnd {
-						activeBlock = c.BlockID
-					} else if c.IsEnd {
-						activeBlock = ""
-					}
-				}
-			} else if activeBlock != "" {
-				rows[r].Cells[trackIdx] = TimelineCell{BlockID: activeBlock}
-			}
-		}
-	}
-
-	return rows
-}