How to hide contacts from left side in Telegram Desktop

Telegram is a fast-growing app which competes with WhatsApp and Viber in the mobile messaging market. Like these apps, it also has a desktop version for Windows, Linux and Mac. There is an issue with the official Telegram Desktop app - it does not give you a clear option to hide the contact list on the left side of its window. Here is a little trick you can use to bypass this limitation.