Bloom (sometimes referred to as light bloom or glow) is a computer graphics effect used in video gamesdemos, and high dynamic range rendering (HDRR) to reproduce an imaging artifact of real-world cameras

What Bloom basically does is increase the luminosity of light source in the software. Whether that light source is sun in an open environment or light bulb in a room. 

You may find while creating your layout that you find the glare too much and so we have added the feature for you to be able to toggle on and off

We would actually recommend turning on when using the Camera Function to take shots of your layouts and off to reduce the glare or even resources being used whilst the software is running idle. 

To locate within the software go tp SETTINGS > OPTIONS and the below box will appear, you are then able to Tick or untick Bloom as you need.