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This simple userscript adds a clickable search button to the Stack Exchange top bar, as the only current way to search is to press enter, which can be confusing for some.
You can select one of two…
Don't like your green rep notifications?
Hide them completely with Banana Stand:
Banana Stand User Script Download Link
Alternatively, make the less intrusive with Banana Stand Lite:
It's the extensible userscript for customising that almost-black bar at the top of your screen.