Fixes Microsoft/monaco-editor#69: Introduce and adopt...

Fixes Microsoft/monaco-editor#69: Introduce and adopt `alwaysConsumeMouseWheel` ScrollableElement option

src/vs/base/browser/ui/list/listView.ts

@@ -87,6 +87,7 @@ export class ListView<T> implements IDisposable {
 
 		this.scrollableElement = new ScrollableElement(this.rowsContainer, {
 			canUseTranslate3d: false,
+			alwaysConsumeMouseWheel: true,
 			horizontal: ScrollbarVisibility.Hidden,
 			vertical: ScrollbarVisibility.Auto,
 			useShadows: getOrDefault(options, o => o.useShadows, DefaultOptions.useShadows),

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

@@ -285,8 +285,10 @@ export class ScrollableElement extends Widget {
 			}
 		}
 
-		e.preventDefault();
-		e.stopPropagation();
+		if (this._options.alwaysConsumeMouseWheel || this._shouldRender) {
+			e.preventDefault();
+			e.stopPropagation();
+		}
 	}
 
 	private _onDidScroll(e:ScrollEvent): void {
@@ -416,6 +418,7 @@ function resolveOptions(opts: ScrollableElementCreationOptions): ScrollableEleme
 		useShadows: (typeof opts.useShadows !== 'undefined' ? opts.useShadows : true),
 		handleMouseWheel: (typeof opts.handleMouseWheel !== 'undefined' ? opts.handleMouseWheel : true),
 		flipAxes: (typeof opts.flipAxes !== 'undefined' ? opts.flipAxes : false),
+		alwaysConsumeMouseWheel: (typeof opts.alwaysConsumeMouseWheel !== 'undefined' ? opts.alwaysConsumeMouseWheel : false),
 		scrollYToX: (typeof opts.scrollYToX !== 'undefined' ? opts.scrollYToX : false),
 		mouseWheelScrollSensitivity: (typeof opts.mouseWheelScrollSensitivity !== 'undefined' ? opts.mouseWheelScrollSensitivity : 1),
 		arrowSize: (typeof opts.arrowSize !== 'undefined' ? opts.arrowSize : 11),

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

@@ -40,6 +40,11 @@ export interface ScrollableElementCreationOptions {
 	 * Defaults to false.
 	 */
 	scrollYToX?: boolean;
+	/**
+	 * Always consume mouse wheel events, even when scrolling is no longer possible.
+	 * Defaults to false.
+	 */
+	alwaysConsumeMouseWheel?: boolean;
 	/**
 	 * A multiplier to be used on the `deltaX` and `deltaY` of mouse wheel scroll events.
 	 * Defaults to 1.
@@ -117,6 +122,7 @@ export interface ScrollableElementResolvedOptions {
 	handleMouseWheel: boolean;
 	flipAxes: boolean;
 	scrollYToX: boolean;
+	alwaysConsumeMouseWheel: boolean;
 	mouseWheelScrollSensitivity: number;
 	arrowSize: number;
 	listenOnDomNode: HTMLElement;

src/vs/base/parts/tree/browser/treeView.ts

@@ -489,6 +489,7 @@ export class TreeView extends HeightMap {
 		this.wrapper.className = 'monaco-tree-wrapper';
 		this.scrollableElement = new ScrollableElement(this.wrapper, {
 			canUseTranslate3d: false,
+			alwaysConsumeMouseWheel: true,
 			horizontal: ScrollbarVisibility.Hidden,
 			vertical: (typeof context.options.verticalScrollMode !== 'undefined' ? context.options.verticalScrollMode : ScrollbarVisibility.Auto),
 			useShadows: context.options.useShadows,