Hallo Boersenfeger.
Teste mal:
CSS
@-moz-document url-prefix("chrome://browser/content/preferences/preferences.xul"){
#showPasswords{
list-style-image: url("data:image/gif;base64,R0lGODlhIgARALMIAAAAAIAAAACAAICAAAAAgIAAgACAgICAgMDAwP8AAAD/AP//AAAA//8A/wD//////yH5BAEAAAgALAAAAAAiABEAAARWEMlJq704awl63yDVLST5hRpQriYqAhwrwy6iwqq80pzn/7fcbLSgCXXIoacYSzp3k1v0SeVJo8AsUdkSmbZF6VHHe2E/p/GsZlGXymws6xS//Op4RAQAOw==") !important;}
#showPasswords .button-text{ margin-left:5px!important;}
#chooseFolder {list-style-image: url("data:image/gif;base64,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") !important;}
#chooseFolder .button-text{ margin-left:5px!important;}
#showCookiesButton {
list-style-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAqhJREFUeNqkk8lPU1EUxr9XXiEFhE62r0hlKgJRg4gUUoY4rCAYYuJCFyaaGNf+Ka5c6MIFutO4g2giQVqUEmNwSkVKCzRAW+kALX3QvsF7XqHgyoU379x3c+73O/ecO3CqquJ/Gk/dxB0efBkHXgewz8xx6GPuNmbWA90Ws0W21pwCJCXWSbKKkXGpGOBYc5cZam4K5wfdltZLbRXVJgs597OpRGLp02L0m3deEXdeMtf8XxkctD59je1+x/CDsWp7vbXcYICO5+HzzcLT1ytUWhyCqanrbGDyiVlKx1mimCOIBmC7YEF51W3XtXtj1YLTGt1KIC+KyKVScHdf1MbkoznSkFZjDgNIMi5bXD1ug9lm3YjGMP7sOcLBEORCAfuZDLwzPs1Hc6QhLTGlAHkFF2pPtbsobZuxFjdGh+Gwn4QsSZr1dHVqRnOkIS0xpQAFWXXqKqqMnE6H/N4eGlsaS7Bvxq/9B4Y82px3+iMMRquRmKMMJJTr9XpuanJaE+e2t4vwez+8U36shCIlX/+gG4osc8SUTiEvYyuXSWc8A91GWmV1OQJngwPu3k44BBvq6orl0KmI2SzSsY0MMUclKOpC+MfnWCaZxFp4HS+evsZKMKJBza0NxXJkGd53fog7O1gPBWLEHNsDTCwHFpbS8c2sYDfh1t3rqD9tp1SRY6egKgo4dj2HrvSANKQlphRAUREVRfGx782rr4n45m5TS70G0zvxvp3XxgVW2sZaeJc0pCWGWI5EFL3ZxOFqkzrSLhgeNnd0nmlwdVhO1JorDezY4tH13GowkAgFvvz6GRUfTYW5iVBK1RY4DECbSTfL6jJD8DjR32jEOfa4HNpFU7C5ksb3DxHMBpOIM9dvemCMlQ4DUCmVB8b/4wXLzHaZ5Rir/BFgAGITa7hxBUPyAAAAAElFTkSuQmCC") !important;}
#showCookiesButton .button-text{ margin-left:5px!important;}
#clearDataSettings {
list-style-image: url("data:image/gif;base64,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") !important;}
#clearDataSettings .button-text{ margin-left:5px!important;}
#setDefaultButton{
list-style-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAClUlEQVQ4ja2TXUhTARzFJXWmWbtbWWoZZlZQaVpbay3Q6KGnejCsHovsgwoK+9KNpq3vSOheB+FHBF4bMbdruykZaXpnZtadGfVyCYKiXqIPkKKih18PYSurl+g8/zn//zn/cxISxsEwDNSIiiRKeNwePG4PkiihRlQMw2D8/C9QVRVRlAiFFaKaRkzXiek6UU0jFFYQRQlVVf9MErgSQJZb6RxSODaym03DNkrvZ1IymEnZwFIO3tpC5E4bstxK4EqA3zbLcistw342DhezSrfgGrLgHBBwaALrugvxPtpJWYeTxugFZLk1folhGIiiRMc9hfJYMa77VlYOWHH0Cdh7BOxdAk9ePeTL18/YQhmsCS+kvS+IKErfPVEjKqGwQm1sFysHrTj7LTh6LNhumClWzZQFXQCc6fay4PIk5jWnURmpIBRWUCMqCZIoEdU0yu/aWHHbwvIuK8tUgaKQmYKAmchIEADHxTzm1qeReyGN0oZCopqGJEokeNweYrrOqp4sbJ0WNt8qoaJ3HYUtFlzN+QAoD66SW5dKztmJzDyZwpxTAjFdx+P2xAmc17NZEhSo7z8NwLbABnwdVQCs9TuYdXoi2b4UMmtM5NROiROMSVh/zc6ilikUNc1g9NMoL9++4P2Hdzx+PsKsE6lk1ZqYfjSZaVVJrDi1OC5hzER3x24WNKaT70/nfNdxxrC1aROZXhPT3clMPZKE5UASe5u3x00ce2OkN8zqS4vJrUvFVpfH249vePb6KbO9ZqZVJ2M9lIRQmUhR7XyUm23xN/4cpIauelz+RWT7UphRYyLjx9ZEzPsnsKRmPv528dcgjY9ye3eIfS07cJ4rYGb1ZLIOp2P3LWRPUwXhm3+J8n8p07/W+RtwnC3itIcCYgAAAABJRU5ErkJggg==") !important;}
#setDefaultButton .button-text{ margin-left:5px!important;}
}
Alles anzeigen
Das ist nur ein Teil.
Rest folgt wenn es funktioniert.
Mfg.
Endor