To clarify, your custom style will still be selectable, but the changes you made will not show if you use the default style. Visual changes don't automatically transfer from one style to another, you have to reproduce them in every style you want to use.
The Twitter icon around your page could be a simple fix. I would need to know:
- which style were you using?
- a screenshot of your Style Properties, specifically Style Properties/General/Content
If we can see this page, we may be able to get a bit more info to help you, or we can try...