An artificial reality system is described that renders, presents, and controls user interface elements within an artificial reality environment, and performs actions in response to one or more detected gestures of the user. The artificial reality system includes an image capture device, a head-mounted display (HMD), a gesture detector, a user interface (UI) engine, and a rendering engine. The image capture device captures image data representative of a physical environment. The HMD outputs artificial reality content. The gesture detector identifies, from the image data, a gesture including a configuration of a hand that is substantially stationary for at least a threshold period of time and positioned such that an index finger and a thumb of the hand form approximately a right angle. The UI engine generates a UI element in response to the identified gesture. The rendering engine renders the UI element as an overlay to the artificial reality content.