Do you mean the find bar at the bottom to search the current page or do you mean the search bar on the Navigation Toolbar?

Is a toolbar or an element on a toolbar has focus then the toolbar stays visible until you remove the focus.

it's the find bar at the bottom, the problem even occur when I open the findbar in one tab and switch between tabs and switch back to the first tab the toolbar stays visible as I said in my first post.

I've tested it and I see that if the find bar has focus that the toolbar at the top stay visible. When the focus if off the find bar and in the browsing area then I need to move the mouse to make the toolbar slide away.