Never tell your colleagues that you plan to resign because there is always somebody who wants your position. It’s another story if you would like to let your boss know that you are planning to quit your job. This is much riskier than keeping it all to yourself. You can get yourself into difficult situations, though again, you should be the judge of that. Be careful when you download a resignation letter template. Someone can catch you. Don't download a letter of resignation template on your corporate machine if you are not sure about your resignation.
An almost natural symptom is putting your CV on a job portal. The HR department of your company will surely find it. You think you can explain this to your management by telling them that you are not actually looking for a job, you simply uploaded your CV. But why would you do that? You can’t beat about the bush if they want answers. Probably you can manage it if you know all the fairy tales of Andersen. Do you?
The safest way to do this is to apply for jobs instead of uploading your CV to job portals and letting companies browse your profiles. A good workaround is to have a Linkedin profile. Keep your resignation letter safe.