WordPress adding p tags when using the HTML tab in the editor

Hello everyone..

I’m facing this problem I’m coding a custom page, using a “Page”, in the HTML tag i’ve been coding some HTML… All looks great, and working (I’ve tested outside WordPress too) – Then I save the page, go load it in wordpress – Nothing looks like it should.. I check the code.. And randomly wordpress add p-tags allover the code.. And all my code is broken – Then I manually sit in Chrome with the webkit inspector, remove all p-tags – Weird enough it’s working as it should – Then I try go code that page again (I’m not even using a p tag in the code) – save the page.. And it adds the p-tags again..

Do I have any control over the HTML tab in pages? – I would like to be able to code what that should be in that page – Not that when I’ve coded something, then it adds more code than I ask about..

Can anybody help?

Doing it both with my custom, but also the Twenty Eleven Theme.