Brown highlight over text


I notice when I open some of the ruby on rails files I have created, they initially open up using the theme selected, but quickly get highlighted in a light brown color. I’m not sure why this is happening? Other files remain in the standard theme coloring.
I am able to read the file and update it but would like to remove the highlighting.
Can someone please advise me how to avoid this.
The only reason it may be happening is the highlighted files are opened from two browsers?


yes, the brown highlight is the selection of other users/ide instances


Many thanks, harutyun, this can be considered closed.