From this comment I can tell you are way out of your depth, and commenting on things you have very little actual understanding of. I'd advise you to dive a little deeper than the surface before making claims.
Taiwan claims all of their former territory in their constitution, adopted in 1947. This was towards the end of the civil war, a few years before the establishment of the PRC, and when the nationalist party of the KMT would retreat to Taiwan. However, since the PRC also claims all the territory of the ROC, seeing themselves as the rightful successor, Taiwan is now locked into their old constitution. Changing the constitution, would be an act of succession and thus war.
This is however not at all in line with either the status quo or public opinion. The status quo is that Taiwan is a fully independent nation, with it's own military, foreign relations, and China has zero influence over the vibrant newly democratic island nation.
In terms of public opinion, the opinion especially now is firmly against re-unification with the PRC, especially under current circumstances. This stance has pretty much always polled abysmal single digit numbers. Some nationalists still favour 'closer' ties with China, both their numbers are decreasing every year. The vast majority of the country favours the status quo independence (out of fear for Chinese military aggression) or declaring independence outright.
So while the legal documents might make those claims, no one actually takes those seriously, or actually wants those claims. However changing them would risk an invasion.
EDIT: When you're too busy cock-sucking an totalitarian oppressive dictatorship that you don't have any time to support actual socialist principles like freedom and equality. Downvote what you want, you don't give a shit about socialism.
You seem to have a very warped view of history.
I do not know what you mean with the use of 'always'. Taiwan was first inhabited by their aborigine people and Hakka immigrants, until the Dutch colonised it around 1624. Then it was annexed by the Qing dynasty. This lead to many many rebellions against their imperial rule. Later it was seceded to Taiwan around the end of the 19th century, and since then it has never been controlled by the PRC.
In recent years China has annexed Tibet, and in the past Taiwan, Manchuria, Korea, and parts of Vietnam to name a few. Where do you think they got their territory from? The people already living there happily gave it away? It was conquered.
China also has a history filled with internal strive, infighting, and constant attempts at greater control. China is already the size where it can be considered an empire. They might not have colonised, but around the time when naval technology was advanced enough to actually start colonies, China was already starting to fall behind some European nations. So your point is quite irrelevant.