diff -r 3855a9396f53 -r 11c917761d56 src/pyams_skin/resources/less/forms.less
--- a/src/pyams_skin/resources/less/forms.less	Tue Oct 23 12:10:39 2018 +0200
+++ b/src/pyams_skin/resources/less/forms.less	Tue Oct 23 15:49:17 2018 +0200
@@ -1815,7 +1815,14 @@
 		border: 1px solid #ccc;
 
 		.prefix {
-			padding: 4px 0 4px 6px;
+			color: @infoTextColor;
+			padding: 6px 0 6px 6px;
+			font: 13px/16px Ubuntu, Helvetica, Arial, sans-serif;
+			height: 16px;
+
+			&:empty {
+				padding: 4px 0;
+			}
 		}
 		.prefix + input {
 			border-width: 0;
@@ -1825,6 +1832,14 @@
 				border-width: 1px 1px 1px 0;
 			}
 		}
+		.prefix:empty + input {
+			padding-left: 8px;
+
+			&:focus {
+				padding-left: 7px;
+				border-width: 1px;
+			}
+		}
 	}
 	.checkbox i,
 	.icon-append,