src/vs/editor/common/viewModel/overviewZoneManager.ts/OverviewZoneManager/setLineHeight
class OverviewZoneManager:	public setLineHeight(lineHeight: number): boolean {
		if (this._lineHeight === lineHeight) {
			return false;
		}
		this._lineHeight = lineHeight;
		this._colorZonesInvalid = true;
		return true;
	}