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

@@ -729,17 +729,20 @@ function labelEditSave() {
 		return
 	}
 
-	var sql_exp = document.forms["label_edit_form"].sql_exp.value;
-	var description = document.forms["label_edit_form"].description.value;
+	if (!is_opera()) {
 
-	if (sql_exp.length == 0) {
-		alert("SQL Expression cannot be blank.");
-		return false;
-	}
+		var sql_exp = document.forms["label_edit_form"].sql_exp.value;
+		var description = document.forms["label_edit_form"].description.value;
 	
-	if (description.length == 0) {
-		alert("Caption field cannot be blank.");
-		return false;
+		if (sql_exp.length == 0) {
+			alert("SQL Expression cannot be blank.");
+			return false;
+		}
+	
+		if (description.length == 0) {
+			alert("Caption field cannot be blank.");
+			return false;
+		}
 	}
 
 	closeInfoBox();
@@ -792,11 +795,13 @@ function filterEditSave() {
 		return
 	}
 
-	var reg_exp = document.forms["filter_edit_form"].reg_exp.value;
+	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;
+		if (reg_exp.length == 0) {
+			alert("Filter expression field cannot be blank.");
+			return;
+		}
 	}
 
 	notify("Saving filter...");