Solved Issue #318 and added states to back button

cmd/mist/assets/qml/views/browser.qml

@@ -129,7 +129,7 @@ Rectangle {
 
 			Button {
 				id: back
-
+                z: 30
 				onClicked: {					
                     webview.goBack()
 				}
@@ -141,7 +141,9 @@ Rectangle {
 
 				style: ButtonStyle {
                     background: Image {
-						source: "../../backButton.png"
+                         source: (webview.canGoBack) ? 
+                            (control.hovered ? "../../backButtonHover.png" : "../../backButton.png") : 
+                            "../../backButtonDisabled.png"
                          width: 20
                          height: 30
                     }
@@ -153,7 +155,7 @@ Rectangle {
                 height: 28
                 color: "#FFFFFF"
                 radius: 6
-
+                z:2
 	           MouseArea {
 			    	anchors.fill: parent
 			    	z: 10
@@ -247,7 +249,7 @@ Rectangle {
 				    }
 			    }
    				
-			    z:2
+			    
 			}
 			
 			Rectangle {
@@ -256,6 +258,7 @@ Rectangle {
 			    height: 30
 			    color: "#BDB6B6"
 			    radius: 6
+                z:1
 
 			    anchors {
 					left: back.right
@@ -265,18 +268,16 @@ Rectangle {
 					top: parent.top 
 					topMargin: 23
 				}				
-
-				z:1
 			}
 
 			Rectangle {
 				id: navBarBackground
                 anchors.fill: parent
+                z:-1
                 gradient: Gradient {
                     GradientStop { position: 0.0; color: "#F6F1F2" }
                     GradientStop { position: 1.0; color: "#DED5D5" }
                 }
-                z:-1
             }
 
             states: [