some opera-related fixes

backend.php

@@ -2281,7 +2281,9 @@
 
 			print "<div align='right'>";
 
-			print "<input type=\"submit\" onclick=\"return labelTest()\" value=\"Test\">
+			$is_disabled = (strpos($_SERVER['HTTP_USER_AGENT'], 'Opera') !== FALSE) ? "disabled" : "";
+
+			print "<input $is_disabled type=\"submit\" onclick=\"return labelTest()\" value=\"Test\">
 				";
 
 			print "<input type=\"submit\" 

functions.js

@@ -7,6 +7,10 @@ function browser_has_opacity() {
 		navigator.userAgent.match("Opera") != null;
 }
 
+function is_opera() {
+	return navigator.userAgent.match("Opera");
+}
+
 function exception_error(location, e, silent) {
 	var msg;
 

prefs.js

@@ -729,6 +729,8 @@ function labelEditSave() {
 		return
 	}
 
+	if (!is_opera()) {
+
 		var sql_exp = document.forms["label_edit_form"].sql_exp.value;
 		var description = document.forms["label_edit_form"].description.value;
 	
@@ -741,6 +743,7 @@ function labelEditSave() {
 			alert("Caption field cannot be blank.");
 			return false;
 		}
+	}
 
 	closeInfoBox();
 
@@ -792,12 +795,14 @@ function filterEditSave() {
 		return
 	}
 
+	if (!is_opera()) {
 		var reg_exp = document.forms["filter_edit_form"].reg_exp.value;
 	
 		if (reg_exp.length == 0) {
 			alert("Filter expression field cannot be blank.");
 			return;
 		}
+	}
 
 	notify("Saving filter...");