diff --git a/app/api/routes.py b/app/api/routes.py
index 2b2461a..62c92de 100644
--- a/app/api/routes.py
+++ b/app/api/routes.py
@@ -341,6 +341,8 @@ def patch_line(request: Request, line_id: str, payload: LinePatch):
     # None deliberately clears a per-level override and restores ATR behavior.
     if "alert_early_points" in payload.model_fields_set:
         changes["alert_early_points"] = payload.alert_early_points
+    if "cutoff_t" in payload.model_fields_set:
+        changes["cutoff_t"] = payload.cutoff_t
     if changes.get("anchor_t") == changes.get("last_t") and "anchor_t" in changes:
         raise HTTPException(400, "Line endpoints must have different times")
     try:
diff --git a/static/app.js b/static/app.js
index fb03437..077341c 100644
--- a/static/app.js
+++ b/static/app.js
@@ -131,6 +131,7 @@ createApp({
     const comments = ref([]);
     const drawingFilter = ref('');
     const drawingKind = ref('all');
+    const drawingTf = ref('all');
     const diagnosticMode = ref(ConfluenceChart.diagnosticMode());
     const captureBusy = ref(false);
     const snap = ref(true);
@@ -284,10 +285,11 @@ createApp({
       const needle = drawingFilter.value.trim().toLowerCase();
       return drawings.value.filter(item => {
         if (drawingKind.value !== 'all' && item.kind !== drawingKind.value) return false;
+        const timeframe = item.line?.tf || item.comment?.tf || '';
+        if (drawingTf.value !== 'all' && timeframe !== drawingTf.value) return false;
         if (!needle) return true;
         // Matched against what is on screen — the label or comment text, the
         // kind, and the drawing number, so "comment", "cpi" and "7" all work.
-        const timeframe = item.line?.tf || item.comment?.tf || '';
         return `${item.label} ${item.kind} ${timeframe} #${item.number}`.toLowerCase().includes(needle);
       });
     });
@@ -1223,6 +1225,6 @@ createApp({
       window.removeEventListener('keydown', handleKeydown);
     });
 
-    return { status, price, sessionOpen, quoteChange, animateCurrentPrice, autoScrollLivePrice, barAge, dataUpdatedAt, buildStamp, timeframe, timeframes, drawingColors, drawingColorRows, drawingColorName, colorRowLabels, symbolChoices, selectedSymbol, symbolColor, symbolScale, symbolScales, symbolPanelOpen, prefs, clusters, clustersByPrice, events, diagnosticMode, captureBusy, captureDiagnostic, armedTool, drawName, drawColor, drawWidth, drawSide, snap, selectedDrawing, selectedDrawings, drawingList, startDrawingListResize, manualLines, hasDrawingSelection, allShownSelected, selectedAreHidden, alertPrice, alertNote, alertEarlyPoints, levelColor, levelWidth, addPriceAlert, armTool, selectTimeframe, allEnabled, toggleGroup, deleteSelected, deleteLine, toggleDrawingSelection, toggleSelectAll, toggleSelectedVisibility, renameLine, updateLineStyle, updateLevelNumber, setArmed, commentText, commentFloat, comments, drawings, filteredDrawings, drawingFilter, drawingKind, deleteDrawing, toggleComment, togglePinned, chooseSymbol, toggleSymbolPanel, startSymbolDrag, dropSymbol, optionExpirations, optionExpiryId, optionSide, optionMode, optionMin, optionMax, optionContracts, optionUnderlying, optionBusy, optionError, optionSearched, optionCopied, onOptionsToggle, searchOptions, copyOption };
+    return { status, price, sessionOpen, quoteChange, animateCurrentPrice, autoScrollLivePrice, barAge, dataUpdatedAt, buildStamp, timeframe, timeframes, drawingColors, drawingColorRows, drawingColorName, colorRowLabels, symbolChoices, selectedSymbol, symbolColor, symbolScale, symbolScales, symbolPanelOpen, prefs, clusters, clustersByPrice, events, diagnosticMode, captureBusy, captureDiagnostic, armedTool, drawName, drawColor, drawWidth, drawSide, snap, selectedDrawing, selectedDrawings, drawingList, startDrawingListResize, manualLines, hasDrawingSelection, allShownSelected, selectedAreHidden, alertPrice, alertNote, alertEarlyPoints, levelColor, levelWidth, addPriceAlert, armTool, selectTimeframe, allEnabled, toggleGroup, deleteSelected, deleteLine, toggleDrawingSelection, toggleSelectAll, toggleSelectedVisibility, renameLine, updateLineStyle, updateLevelNumber, setArmed, commentText, commentFloat, comments, drawings, filteredDrawings, drawingFilter, drawingKind, drawingTf, deleteDrawing, toggleComment, togglePinned, chooseSymbol, toggleSymbolPanel, startSymbolDrag, dropSymbol, optionExpirations, optionExpiryId, optionSide, optionMode, optionMin, optionMax, optionContracts, optionUnderlying, optionBusy, optionError, optionSearched, optionCopied, onOptionsToggle, searchOptions, copyOption };
   },
 }).mount('#app');
diff --git a/static/chart.js b/static/chart.js
index eb9a6cb..0d0f50c 100644
--- a/static/chart.js
+++ b/static/chart.js
@@ -40,6 +40,7 @@ class ConfluenceChart {
     this.contextCutoff = null;
     this.contextLineId = null;
     this.contextEndButton = null;
+    this.contextExtendButton = null;
     this.contextListener = null;
     this.onLineEnd = null;
     this.onLineDuplicate = null;
@@ -319,10 +320,18 @@ class ConfluenceChart {
       this.endSelectedLineHere();
     });
     this.contextEndButton = endHere;
+    const extend = document.createElement('button');
+    extend.type = 'button';
+    extend.textContent = 'Extend trendline';
+    extend.addEventListener('click', event => {
+      event.stopPropagation();
+      this.extendSelectedLine();
+    });
+    this.contextExtendButton = extend;
     const duplicate = document.createElement('button');
     duplicate.type = 'button';
     duplicate.dataset.action = 'duplicate';
-    duplicate.textContent = 'Duplicate 10 bars right';
+    duplicate.textContent = 'Duplicate';
     duplicate.addEventListener('click', event => {
       event.stopPropagation();
       const level = this.levels.find(value => value.id === this.contextLineId);
@@ -340,7 +349,7 @@ class ConfluenceChart {
       if (id && this.onLineDelete) this.onLineDelete(id);
     });
     this.contextMenu.addEventListener('click', event => event.stopPropagation());
-    this.contextMenu.append(endHere, duplicate, deleteLine);
+    this.contextMenu.append(endHere, extend, duplicate, deleteLine);
     this.overlayLayer.appendChild(this.contextMenu);
     this.priceTag = document.createElement('div');
     this.priceTag.className = 'chart-price-tag';
@@ -2200,6 +2209,7 @@ class ConfluenceChart {
     this.contextLineId = level.id;
     this.contextCutoff = cutoff > level.last_t ? cutoff : null;
     this.contextEndButton.hidden = this.contextCutoff == null;
+    this.contextExtendButton.hidden = level.cutoff_t == null;
     this.contextMenu.hidden = false;
     const plot = this.plotCanvas().getBoundingClientRect();
     this.contextMenu.style.left = `${Math.max(4, Math.min(point.x, plot.width - 170))}px`;
@@ -2229,6 +2239,17 @@ class ConfluenceChart {
     if (this.onLineEnd) this.onLineEnd({ ...level });
   }
 
+  extendSelectedLine() {
+    const level = this.levels.find(value => value.id === this.selectedLineId);
+    if (!level || level.cutoff_t == null) return;
+    level.cutoff_t = null;
+    const entry = this.levelSeries.get(level.id);
+    if (entry) entry.series.setData(this.seriesLineData(level));
+    this.renderLineBridges();
+    this.hideContextMenu();
+    if (this.onLineEnd) this.onLineEnd({ ...level });
+  }
+
   // Tinted by the bar's own direction, muted so the candles stay the subject.
   static toVolume(bar) {
     return {
diff --git a/static/index.html b/static/index.html
index 465d1f3..66a2897 100644
--- a/static/index.html
+++ b/static/index.html
@@ -231,7 +231,11 @@
               <option value="comment">Comments</option>
               <option value="symbol">Symbols</option>
             </select>
-            <input v-model="drawingFilter" placeholder="Filter by text…" aria-label="Filter drawings by text">
+            <select v-model="drawingTf" aria-label="Filter drawings by timeframe">
+              <option value="all">All TFs</option>
+              <option v-for="tf in timeframes" :key="tf" :value="tf">{{ tf }}</option>
+            </select>
+            <input v-model="drawingFilter" placeholder="Filter text" aria-label="Filter drawings by text">
           </div>
           <div class="trendline-actions" v-if="drawings.length">
             <button @click="toggleSelectAll" :disabled="!filteredDrawings.length">{{ allShownSelected ? 'Clear shown' : 'Select shown' }}</button>
diff --git a/static/style.css b/static/style.css
index 81884fa..069349d 100644
--- a/static/style.css
+++ b/static/style.css
@@ -105,7 +105,7 @@ aside { padding:16px; }h2 { margin:0 0 12px; color:var(--muted); font-size:11px;
 .option-row { display:grid; grid-template-columns:1fr 1fr 1fr auto; gap:4px; align-items:center; padding:3px 0; border-bottom:1px solid var(--line); font-size:10px; }
 .option-row.option-head { color:var(--muted); text-transform:uppercase; letter-spacing:.3px; font-size:8px; }
 .option-row button { padding:2px 6px; font-size:8px; }
-.drawing-filters { display:grid; grid-template-columns:auto 1fr; gap:6px; margin-bottom:8px; }
+.drawing-filters { display:grid; grid-template-columns:auto auto 1fr; gap:6px; margin-bottom:8px; }
 .drawing-filters select, .drawing-filters input { font:inherit; font-size:10px; padding:4px 6px;
   border:1px solid var(--line); border-radius:5px; background:transparent; color:var(--fg); min-width:0; }
 .drawing-icon { display:flex; align-items:center; justify-content:center; color:var(--muted); font-size:10px; }
diff --git a/tests/test_manual_lines.py b/tests/test_manual_lines.py
index 81e4e33..d234852 100644
--- a/tests/test_manual_lines.py
+++ b/tests/test_manual_lines.py
@@ -136,3 +136,27 @@ def test_every_drawing_gets_a_number_including_comments(tmp_path):
     third = store.add(ManualLine(id="ml_c", slope=1.0, **common))
 
     assert [first.number, note.number, third.number] == [1, 2, 3]
+
+
+def test_a_null_cutoff_clears_an_ended_line(tmp_path):
+    from fastapi import FastAPI
+    from fastapi.testclient import TestClient
+
+    from app.api.routes import router
+    from app.config import Settings
+    from app.runtime import Runtime
+
+    app = FastAPI()
+    app.include_router(router)
+    app.state.runtime = Runtime(Settings(manual_lines_path=tmp_path / "manual_lines.json"))
+    client = TestClient(app)
+    created = client.post("/api/lines", json={
+        "tf": "1m", "side": "support",
+        "anchor_t": 100, "anchor_p": 1.0,
+        "end_t": 200, "end_p": 2.0,
+        "cutoff_t": 150,
+    }).json()
+    assert created["cutoff_t"] == 150
+
+    cleared = client.patch(f"/api/lines/{created['id']}", json={"cutoff_t": None}).json()
+    assert cleared["cutoff_t"] is None