I have a "Search and Replace" button and all I can do is move it.. When I right-click on it it only shows options to move it to an other sidebar, or to "Make Persistant".. I have tried going to Settings menu and unchecking menu bar, show toolbar, show status bar, and show tabs, and I STILL see it.. I have gone in to toolbar settings, and I have 2 toolbars I can edit.. One is called "Main Toolbar <kate>" and other is "Main Toolbar <KatePartView>".. The kate one is empty already.. And the katepartview one only has 4 things that I put in it.. Neither one of them have "Search and Replace" enabled, so I can't even remove it.. The search and replace button takes up a whole toolbar line even though it is just 1 button.. Any where I move it to, it does not merge in to any other toolbar or status bar, so it is wasted space, and a button that I never use.. If I want to use replace I just use the keyboard shortcut.. I've used kate for many years for making bash scripts.. I'm not sure which update added this annoying button and empty space, but as far as I can tell it is unremovable..
If you don't need the Search in files feature: Settings->Configure Kate -> Application -> Plugins: un-check "Search & Replace" If you just don't want to see the "icon" you can hide the sidebars: View -> Tool Views -> Show Sidebars (ctrl+alt+shift+F)