skins2: correct forgotten position and set default values

modules/gui/skins2/src/generic_window.cpp

@@ -170,10 +170,12 @@ void* GenericWindow::getOSHandle() const
 
 void GenericWindow::setParent( GenericWindow* pParent, int x, int y, int w, int h )
 {
-    // Update the window size
-    m_width = w;
-    m_height = h;
+    // Update the window size and position
+    m_left = x;
+    m_top = y;
+    m_width  = ( w > 0 ) ? w : m_width;
+    m_height = ( h > 0 ) ? h : m_height;
 
     void* handle = pParent ? pParent->getOSHandle() : NULL;
-    m_pOsWindow->reparent( handle, x, y, w, h );
+    m_pOsWindow->reparent( handle, m_left, m_top, m_width, m_height );
 }

modules/gui/skins2/src/generic_window.hpp

@@ -96,7 +96,8 @@ public:
     void* getOSHandle() const;
 
     /// reparent
-    void setParent( GenericWindow* pParent, int x, int y, int w, int h );
+    void setParent( GenericWindow* pParent,
+                    int x = 0, int y = 0, int w = -1, int h = -1 );
 
 protected:
     /// Get the OS window