Is this also true if there is a double taxation treaty between Norway and the other country? I would think not.
Norway have agreements with a lot of other countries which lets you deduct whatever taxes you pay in the country you are a resident. However, as it is almost impossible to find any country with higher taxes, you always ends up paying Norwegian tax anyways minus whatever you have already paid to whichever country you live in. I think Norway and the US is the only two countries that tax their citizens regardless where they live. My wife is American, but she has never paid any tax to the US since we moved to Norway, as the Norwegian tax rate is so much higher and she can deduct the Norwegian taxes from the US taxes she would be obliged to pay.
In OPs case, it may not be beneficial to do this. Depends heavily on his situation, but if he's truly roaming it's likely not the best solution.
There's no "here in Europe" at all, it's different for each country. What country are you from that has such stringent and obtrusive requirements? I registered as a non-resident and that was it. I could provide a rental contract if required but wasn't asked. What business is it of your previous resident country if you even have a bank account, telephone number, drivers' license or health insurance in your new residency - these are not requirements for everyone. And taxing someone on the difference when they lived years elsewhere is absurd and unheard of.
Taxman in developed high tax EU countries operate with very similar methods. It doesn't matter if it's "absurd or unheard of" to you.
If you do not want to name yours I understand but could you list some of these countries for the readers' information.
Just some advice as I have been doing this for six years. When you talk to a tax advisor you often hear something conflicting afterwards on Facebook or other. So you speak to another, different again and then you have multiple versions of reality. When I left the UK I asked the HMRC call centre to advise me directly, recording all my calls*. Horse's mouth and they do this for free. This proved useful as due to a matter of a few pounds of interest gained between filling the forms and posting them, I had a glitch. I had however anticipated this and asked their call centre guy, he said it was not important. They wanted me to refile but on hearing him say it would not be needed, the advisor just said, OK that's the advice we gave so we will correct it. This year due to the pandemic lockdowns I was unable to leave for Panamá and went over 183 days in Colombia which happens to be like the US a global income (miked for residency/citizenship) system and a wealth tax. There are only a handful of countries that do this. Yemen another they say. Well again, I got out of a massive bill easily with a recording. I own a number of properties and with one exception, I pay no local taxes on rental income, in one country in Africa I do pay tax on this income due to the national law on foreign owners. Its fun for a while, you may get 10 years before you decide to land somewhere. I'm at 6 and may pick a home soon. What is sure is some peeps will always believe there must be a catch and there must be some crime involved For most people of the world, not the case. CRS, common reporting system exists allowing most national tax offices to full records on you bank accounts but not so important until you eventually become resident. Also if you trade US markets and have a family, the US takes a massive percentage of assets there when a non-resident dies. Its insane but that's what they do so plan for that. *In the UK six years ago anyway when the automated system says calls may be recorded for training etc. you are free to record as there is no expectation of privacy.
Again, so unnecessarily complicated. If you are trading full-time (non-US citizen), simply establish a BVI corporation, and trade through it. You are no longer a "tax resident/tax home" of anywhere, your offshore entity now is. If you actually own businesses/other on Canadian soil, then a whole different story, as you have to follow their laws. Please do consult with a professional attorney.