Index: sources/gui/qml/components/StackItem.qml
===================================================================
diff -u -r074b32b5cc08f41f2d9ce0d021f2151b76bba5ad -r76f632ce5a9039ae662d9a52286079b772f8ae7f
--- sources/gui/qml/components/StackItem.qml	(.../StackItem.qml)	(revision 074b32b5cc08f41f2d9ce0d021f2151b76bba5ad)
+++ sources/gui/qml/components/StackItem.qml	(.../StackItem.qml)	(revision 76f632ce5a9039ae662d9a52286079b772f8ae7f)
@@ -30,16 +30,47 @@
     width : Variables.applicationWidth
     height: Variables.applicationHeight
 
-    function pop () {
-        _stackView.pop()
+    function info() {
+        for( var i = 0; i < _stackView.depth; i++ ) {
+            console.debug("index:", i, _stackView.get(i))
+        }
     }
 
+    function back(vScreen) {
+        if (stackView.find(function(screen) {
+              return screen === vScreen;
+          })) {
+            _stackView.pop(vScreen)
+        }
+        else {
+            _stackView.push(vScreen)
+        }
+        info()
+    }
+
+    function pop (vScreen) {
+        _stackView.pop(vScreen)
+        info()
+    }
+
     function push (vScreen) {
-        _stackView.push(vScreen)
+        if ( _stackView.currentItem === vScreen) {
+            console.debug("same current screen didn't push" , vScreen.name)
+        }
+        else {
+            _stackView.push(vScreen)
+        }
+        info()
     }
 
-    function popToItem(item) {
-        _stackView.pop(item);
+    function replace(vScreen, vReplaced) {
+        if (vReplaced === undefined) {
+            _stackView.replace(_stackView.currentItem, vScreen)
+        }
+        else {
+            _stackView.replace(vReplaced, vScreen)
+        }
+        info()
     }
 
     StackView { id  : _stackView