Was this button at the bottom of your web browser window? Or was it in the task bar of your screen desktop?

I use Internet Explorer, and at the bottom right corner there is a button that says 100%, and it has a drop down arrow I can click to change the zoom level of the text. Is that what you mean?
I noticed that if I go to the menus at the top left, click View>Status Bar, it will disappear, and if I select that again it will reappear.

I realize that this may not be at all what you are talking about, so if it's not, I apologize! I hope you get it back soon.