This rule definitely works - I tested it in Chrome, Firefox and Internet Explorer;
If you're still seeing the search box, make sure your browser cache is cleared. If you're still seeing the search box after clearing the browser cache, perhaps something like security software (e.g. anti-virus) or a browser extension is causing HTTPS filtering to fail?
well i enter it now in adgaurd and it doesnt even recognise twitter.com$$form[id="global-nav-search"] as a valid user rule i type it all in hit the little tick next to it then it all jsut dissappears and it doesnt save please help i jsut reinstalled chrome it does the same thing and its the only browser that will work with my pc
The code Boo has posted should work, if when you restart the browser or machine and the search bar is visible on twitter then you need to check to see if the code is still in adguard (click the adguard icon > adguard settings > check your user filters) if the code is still there and so is the twitter search bar then you need to try disabling all your other browser extensions to see one of them is conflicting with adguard.
I tried boo's code in Firefox with sandboxie on and all seemed to work fine. Of cause i had to find a random twitter page as i dont use it myself.