Nonononono, fuck!
This shouldn't be allowed to happen. They already fucked the ogre with the last movie, which had a completely invalid premise. Rumpelstiltskin convinced the king and queen to sign away their kingdom to save their daughter because Shrek's wish caused him to never exist thus he couldn't save The Princess.
NO!
The whole "Princess in the Tower" schtick was cooked up by The King & The Fairy Godmother as a scheme as part of the payment for her turning The Frog into The Prince, who could then marry the then Princess [who is the current Queen] and became King when the current King & Queen died, which is exactly what happened. Prince Charming was always meant to faux-rescue The Princess from the tower, who would then marry Prince Charming, making him King when the current King & Queen died, which is what The Fairy Grandmother wanted as payment. The King knew this, keeping it concealed from his wife, The Queen. He never would have signed away his kingdom to Rumpelstiltskin knowing that Prince Charming was going to "rescue" The Princess because of the collusion between him and The Fairy Godmother. Shrek just happened to fuck up The King's plan with The Fairy Godmother by rescuing The Princess before Prince Charming showed up because that was what Lord Farquaad wanted as payment to make the swamp Shrek lived in his rightful property under the law. This was the entire premise of the second fucking movie!
As a result the 4th movie is complete garbage and can't be cannon. How the fuckers that wrote and made the 4th movie couldn't keep continuity with the 2nd movie is beyond me. It's not that fucking difficult to see their idea was retarded. I'm not fucking Fermi but if I could see it, it should be obvious to the people who are making the damn thing!
Rate me autistic all you want, but one doesn't need to be an autist to see that the people writing this shit are retarded.