diff --git a/desktop.php b/desktop.php
index d173891..da41708 100644
--- a/desktop.php
+++ b/desktop.php
@@ -118,16 +118,8 @@
                 if (interactivePlot)   
                     msg += ' <br/> <p align="center"><input id="killopBtn" type="button" value="Kill process" /></p>';
 
-                var mask = Ext.getBody().mask(msg);
+                var mask = Ext.getBody().mask(msg, 'amda-mask');
 
-                mask.dom.style.zIndex = '99998';
- 
-                var maskMsg = Ext.DomQuery.select('div[class=x-mask-msg]');
-                if (maskMsg)
-                    maskMsg = maskMsg[0];
-    
-                if (maskMsg)
-                    maskMsg.style.zIndex = '99999';
                 if (interactivePlot)
                 {
                     var killBtn = Ext.get('killopBtn');
diff --git a/js/resources/css/amda.css b/js/resources/css/amda.css
index 40acfa9..4217d8a 100644
--- a/js/resources/css/amda.css
+++ b/js/resources/css/amda.css
@@ -587,3 +587,15 @@ p + p {
 	padding: 4px;
 	white-space: normal;
 }
+
+.amda-mask {
+	z-index: 99999;
+}
+
+.x-mask {
+    filter: alpha(opacity=50);
+    opacity: .5;
+    background: #ccc;
+    cursor: default;
+    z-index: 99998;
+}
--
libgit2 0.21.2