When I erase something in the "visual" tab the code from the "text" tab is getting erased too. When I write something in the visual tab it's appearing in the text tab. Somehow, they both got linked together and it's forcing me to have the same thing in each tab. What's going on?
Download the plugin Preserved HTML Markup Editor. I use it on all my blogs, and it would probably address your problem as well, for it makes sure that WYSIWYG edits don't rearrange / remove spacing, etc, from your HTML tab.