Not sure if this is something that can be fixed on teamviewers side or if this is just a chrome issue, but, when using chrome os to connect to a windows box in fullscreen mode, if you press the esc key, chrome will exit fullscreen mode.
Not sure if there's a more appropriate place to submit bugs so I'm just posting this here. I've resorted to using a windows keymapper to map a different key to esc as a workaround
Unfortunately, this behavior makes TeamViewer almost useless for some applications where the Escape key is used constantly... They could at least have a configuration option to toggle it.