Fix Microsoft/monaco-editor#1353. Use wheel event for modern browsers.

src/vs/base/browser/mouseEvent.ts

@@ -160,6 +160,8 @@ export class StandardWheelEvent {
 				this.deltaY = e1.wheelDeltaY / 120;
 			} else if (typeof e2.VERTICAL_AXIS !== 'undefined' && e2.axis === e2.VERTICAL_AXIS) {
 				this.deltaY = -e2.detail / 3;
+			} else {
+				this.deltaY = -e.deltaY / 40;
 			}
 
 			// horizontal delta scroll
@@ -171,6 +173,8 @@ export class StandardWheelEvent {
 				}
 			} else if (typeof e2.HORIZONTAL_AXIS !== 'undefined' && e2.axis === e2.HORIZONTAL_AXIS) {
 				this.deltaX = -e.detail / 3;
+			} else {
+				this.deltaX = -e.deltaX / 40;
 			}
 
 			// Assume a vertical scroll if nothing else worked
@@ -195,4 +199,4 @@ export class StandardWheelEvent {
 			}
 		}
 	}
-}
\ No newline at end of file
+}

src/vs/base/browser/ui/scrollbar/scrollableElement.ts

@@ -4,6 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import 'vs/css!./media/scrollbars';
+import { isEdgeOrIE } from 'vs/base/browser/browser';
 import * as dom from 'vs/base/browser/dom';
 import { FastDomNode, createFastDomNode } from 'vs/base/browser/fastDomNode';
 import { IMouseEvent, StandardWheelEvent, IMouseWheelEvent } from 'vs/base/browser/mouseEvent';
@@ -312,7 +313,7 @@ export abstract class AbstractScrollableElement extends Widget {
 				this._onMouseWheel(new StandardWheelEvent(browserEvent));
 			};
 
-			this._mouseWheelToDispose.push(dom.addDisposableListener(this._listenOnDomNode, 'mousewheel', onMouseWheel));
+			this._mouseWheelToDispose.push(dom.addDisposableListener(this._listenOnDomNode, isEdgeOrIE ? 'mousewheel' : 'wheel', onMouseWheel));
 		}
 	}
 

src/vs/editor/browser/controller/mouseHandler.ts

@@ -123,7 +123,7 @@ export class MouseHandler extends ViewEventHandler {
 				e.stopPropagation();
 			}
 		};
-		this._register(dom.addDisposableListener(this.viewHelper.viewDomNode, 'mousewheel', onMouseWheel, true));
+		this._register(dom.addDisposableListener(this.viewHelper.viewDomNode, browser.isEdgeOrIE ? 'mousewheel' : 'wheel', onMouseWheel, true));
 
 		this._context.addEventHandler(this);
 	}