diff --git a/src/browser/Terminal.ts b/src/browser/Terminal.ts
index b072c92c..57099ac2 100644
--- a/src/browser/Terminal.ts
+++ b/src/browser/Terminal.ts
@@ -957,11 +957,6 @@ export class Terminal extends CoreTerminal implements ITerminal {
   }
 
   public addMarker(cursorYOffset: number): IMarker | undefined {
-    // Disallow markers on the alt buffer
-    if (this.buffer !== this.buffers.normal) {
-      return;
-    }
-
     return this.buffer.addMarker(this.buffer.ybase + this.buffer.y + cursorYOffset);
   }
 
diff --git a/src/common/buffer/BufferSet.test.ts b/src/common/buffer/BufferSet.test.ts
index 894ebb20..944b8c15 100644
--- a/src/common/buffer/BufferSet.test.ts
+++ b/src/common/buffer/BufferSet.test.ts
@@ -71,4 +71,14 @@ describe('BufferSet', () => {
       assert.equal(bufferSet.active.y, 10);
     });
   });
+
+  describe('markers', () => {
+    it('should clear the markers when the buffer is switched', () => {
+      bufferSet.activateAltBuffer();
+      bufferSet.alt.addMarker(1);
+      assert.equal(bufferSet.alt.markers.length, 1);
+      bufferSet.activateNormalBuffer();
+      assert.equal(bufferSet.alt.markers.length, 0);
+    });
+  });
 });
diff --git a/src/common/buffer/BufferSet.ts b/src/common/buffer/BufferSet.ts
index de220e8f..7d07cec8 100644
--- a/src/common/buffer/BufferSet.ts
+++ b/src/common/buffer/BufferSet.ts
@@ -83,6 +83,7 @@ export class BufferSet extends Disposable implements IBufferSet {
     // The alt buffer should always be cleared when we switch to the normal
     // buffer. This frees up memory since the alt buffer should always be new
     // when activated.
+    this._alt.clearAllMarkers();
     this._alt.clear();
     this._activeBuffer = this._normal;
     this._onBufferActivate.fire({