Fix bug when selection end is less than start

src/SelectionManager.test.ts

@@ -166,15 +166,4 @@ describe('SelectionManager', () => {
       assert.equal(selectionManager.selectionText, '1\n2\n3\n4\n5');
     });
   });
-
-  describe('selectionText', () => {
-    it('should return the empty string when start or end selections are not set', () => {
-      assert.equal(selectionManager.selectionText, '');
-      selectionManager.model.selectionStart = [0, 0];
-      assert.equal(selectionManager.selectionText, '');
-      selectionManager.model.selectionStart = null;
-      selectionManager.model.selectionEnd = [0, 0];
-      assert.equal(selectionManager.selectionText, '');
-    });
-  });
 });

src/SelectionModel.test.ts

@@ -106,10 +106,6 @@ describe('SelectionManager', () => {
       model.selectionEnd = [1, 2];
       assert.equal(model.finalSelectionEnd, null);
     });
-    it('should return null if there is no selection end or selection start length', () => {
-      model.selectionStart = [1, 2];
-      assert.equal(model.finalSelectionEnd, null);
-    });
     it('should return selection start + length if there is no selection end', () => {
       model.selectionStart = [2, 2];
       model.selectionStartLength = 2;

src/SelectionModel.ts

@@ -73,9 +73,6 @@ export class SelectionModel {
 
     // Use the selection start if the end doesn't exist or they're reversed
     if (!this.selectionEnd || this._areSelectionValuesReversed()) {
-      if (this.selectionStartLength === 0) {
-        return null;
-      }
       return [this.selectionStart[0] + this.selectionStartLength, this.selectionStart[1]];
     }