Implemented TAB navigation to switch source.

Mixer.cpp

@@ -394,6 +394,19 @@ void Mixer::setCurrentSource(int index)
     setCurrentSource( session_->find(index) );
 }
 
+void Mixer::setCurrentNext()
+{
+    SourceList::iterator it = current_source_;
+
+    it++;
+
+    if (it == session_->end())  {
+        it = session_->begin();
+    }
+
+    setCurrentSource( it );
+}
+
 void Mixer::unsetCurrentSource()
 {
     // discard overlay for previously current source

Mixer.h

@@ -48,6 +48,7 @@ public:
     void setCurrentSource(Node *node);
     void setCurrentSource(int index);
     void setCurrentSource(Source *s);
+    void setCurrentNext();
     void unsetCurrentSource();
     void cloneCurrentSource();
     void deleteCurrentSource();

UserInterfaceManager.cpp

@@ -279,6 +279,9 @@ void UserInterface::handleKeyboard()
             // button home to toggle menu
             else if (ImGui::IsKeyPressed( GLFW_KEY_INSERT ))
                 navigator.togglePannelNew();
+            // button tab to select next
+            else if (ImGui::IsKeyPressed( GLFW_KEY_TAB ))
+                Mixer::manager().setCurrentNext();
         }
     }