diff --git a/src/browser/selection/SelectionModel.test.ts b/src/browser/selection/SelectionModel.test.ts
index 5f813d7ee..10ca79a34 100644
--- a/src/browser/selection/SelectionModel.test.ts
+++ b/src/browser/selection/SelectionModel.test.ts
@@ -64,6 +64,13 @@ describe('SelectionModel', () => {
       assert.deepEqual(model.finalSelectionStart, undefined);
       assert.deepEqual(model.finalSelectionEnd, undefined);
     });
+    it('should reset selection start to origin when start row is trimmed', () => {
+      model.selectionStart = [50, 0];
+      model.selectionEnd = [10, 2];
+      assert.equal(model.handleTrim(1), true);
+      assert.deepEqual(model.finalSelectionStart, [0, 0]);
+      assert.deepEqual(model.finalSelectionEnd, [10, 1]);
+    });
   });
 
   describe('finalSelectionStart', () => {
diff --git a/src/browser/selection/SelectionModel.ts b/src/browser/selection/SelectionModel.ts
index 7b62b230b..8f87f17e2 100644
--- a/src/browser/selection/SelectionModel.ts
+++ b/src/browser/selection/SelectionModel.ts
@@ -135,9 +135,10 @@ export class SelectionModel {
       return true;
     }
 
-    // If the selection start is trimmed, ensure the start column is 0.
+    // If the selection start row is trimmed away, reset to the buffer origin.
     if (this.selectionStart && this.selectionStart[1] < 0) {
-      this.selectionStart[1] = 0;
+      this.selectionStart = [0, 0];
+      return true;
     }
     return false;
   }
diff --git a/src/browser/services/SelectionService.ts b/src/browser/services/SelectionService.ts
index 576bdc525..39d8dd76b 100644
--- a/src/browser/services/SelectionService.ts
+++ b/src/browser/services/SelectionService.ts
@@ -704,7 +704,7 @@ export class SelectionService extends Disposable implements ISelectionService {
         if (this._activeSelectionMode !== SelectionMode.COLUMN) {
           this._model.selectionEnd[0] = this._bufferService.cols;
         }
-        this._model.selectionEnd[1] = Math.min(buffer.ydisp + this._bufferService.rows, buffer.lines.length - 1);
+        this._model.selectionEnd[1] = Math.min(buffer.ydisp + this._bufferService.rows - 1, buffer.lines.length - 1);
       } else {
         if (this._activeSelectionMode !== SelectionMode.COLUMN) {
           this._model.selectionEnd[0] = 0;