src/vs/base/common/keyCodes.ts/SimpleKeybinding/isDuplicateModifierCase
class SimpleKeybinding:	public isDuplicateModifierCase(): boolean {
		return (
			(this.ctrlKey && this.keyCode === KeyCode.Ctrl)
			|| (this.shiftKey && this.keyCode === KeyCode.Shift)
			|| (this.altKey && this.keyCode === KeyCode.Alt)
			|| (this.metaKey && this.keyCode === KeyCode.Meta)
		);
	}