src/vs/editor/common/viewModel/viewModelImpl.ts/ViewModel/setHiddenAreas
class ViewModel:	public setHiddenAreas(ranges: Range[]): void {
		let lineMappingChanged = false;
		try {
			const eventsCollector = this._eventDispatcher.beginEmitViewEvents();
			lineMappingChanged = this._lines.setHiddenAreas(ranges);
			if (lineMappingChanged) {
				eventsCollector.emitViewEvent(new viewEvents.ViewFlushedEvent());
				eventsCollector.emitViewEvent(new viewEvents.ViewLineMappingChangedEvent());
				eventsCollector.emitViewEvent(new viewEvents.ViewDecorationsChangedEvent(null));
				this._cursor.onLineMappingChanged(eventsCollector);
				this._decorations.onLineMappingChanged();
				this.viewLayout.onFlushed(this.getLineCount());
				this.viewLayout.onHeightMaybeChanged();
			}
		} finally {
			this._eventDispatcher.endEmitViewEvents();
		}
		this._updateConfigurationViewLineCount.schedule();

		if (lineMappingChanged) {
			this._eventDispatcher.emitOutgoingEvent(new ViewZonesChangedEvent());
		}
	}