While solving a puzzle I noticed that switching between tabs deletes the arrows I drew. I'm pretty sure this is an unwanted behaviour since it doesn't occur while playing a game or using some other feature.
Tested on Chrome 62.0.3202.94 and Firefox 57.0 on Windows 7 Home Premium
Tested on Chrome 62.0.3202.94 and Firefox 57.0 on Windows 7 Home Premium