-Some fixes to drag and drop and canvas offset for GUI that were introduced after rewrite

scene/gui/control.cpp

@@ -606,14 +606,14 @@ void Control::force_drag(const Variant& p_data,Control *p_control) {
 	ERR_FAIL_COND(!is_inside_tree());
 	ERR_FAIL_COND(p_data.get_type()==Variant::NIL);
 
-	get_viewport()->_gui_force_drag(p_data,p_control);
+	get_viewport()->_gui_force_drag(this,p_data,p_control);
 
 }
 
 void Control::set_drag_preview(Control *p_control) {
 
 	ERR_FAIL_COND(!is_inside_tree());
-	get_viewport()->_gui_set_drag_preview(p_control);
+	get_viewport()->_gui_set_drag_preview(this,p_control);
 }
 
 
@@ -2046,6 +2046,26 @@ Vector2 Control::get_scale() const{
 	return data.scale;
 }
 
+Control *Control::get_root_parent_control() const {
+
+	const CanvasItem *ci=this;
+	const Control *root=this;
+
+	while(ci) {
+
+		const Control *c = ci->cast_to<Control>();
+		if (c) {
+			root=c;
+
+			if (c->data.RI || c->data.MI || c->is_toplevel_control())
+				break;
+		}
+
+		ci=ci->get_parent_item();
+	}
+
+	return const_cast<Control*>(root);
+}
 
 void Control::_bind_methods() {
 

scene/gui/control.h

@@ -360,6 +360,8 @@ public:
 
 	virtual bool is_text_field() const;
 
+	Control *get_root_parent_control() const;
+
 	Control();	
 	~Control();
 	

scene/main/viewport.cpp

@@ -1460,7 +1460,7 @@ Control* Viewport::_gui_find_control(const Point2& p_global)  {
 		Matrix32 xform;
 		CanvasItem *pci = sw->get_parent_item();
 		if (pci)
-			xform=pci->get_global_transform();
+			xform=pci->get_global_transform_with_canvas();
 
 
 		Control *ret = _gui_find_control_at_pos(sw,p_global,xform,gui.focus_inv_xform);
@@ -1477,7 +1477,7 @@ Control* Viewport::_gui_find_control(const Point2& p_global)  {
 		Matrix32 xform;
 		CanvasItem *pci = sw->get_parent_item();
 		if (pci)
-			xform=pci->get_global_transform();
+			xform=pci->get_global_transform_with_canvas();
 
 
 		Control *ret = _gui_find_control_at_pos(sw,p_global,xform,gui.focus_inv_xform);
@@ -1979,17 +1979,17 @@ void Viewport::_gui_remove_from_modal_stack(List<Control*>::Element *MI,ObjectID
 	}
 }
 
-void Viewport::_gui_force_drag(const Variant& p_data,Control *p_control) {
+void Viewport::_gui_force_drag(Control *p_base, const Variant& p_data, Control *p_control) {
 
 	gui.drag_data=p_data;
 	gui.mouse_focus=NULL;
 
 	if (p_control) {
-		_gui_set_drag_preview(p_control);
+		_gui_set_drag_preview(p_base,p_control);
 	}
 }
 
-void Viewport::_gui_set_drag_preview(Control *p_control) {
+void Viewport::_gui_set_drag_preview(Control *p_base, Control *p_control) {
 
 	ERR_FAIL_NULL(p_control);
 	ERR_FAIL_COND( !((Object*)p_control)->cast_to<Control>());
@@ -2001,7 +2001,7 @@ void Viewport::_gui_set_drag_preview(Control *p_control) {
 	}
 	p_control->set_as_toplevel(true);
 	p_control->set_pos(gui.last_mouse_pos);
-	add_child(p_control); //add as child of viewport
+	p_base->get_root_parent_control()->add_child(p_control); //add as child of viewport
 	p_control->raise();
 	if (gui.drag_preview) {
 		memdelete( gui.drag_preview );

scene/main/viewport.h

@@ -246,8 +246,8 @@ friend class Control;
 	void _gui_remove_control(Control *p_control);
 	void _gui_hid_control(Control *p_control);
 
-	void _gui_force_drag(const Variant& p_data,Control *p_control);
-	void _gui_set_drag_preview(Control *p_control);
+	void _gui_force_drag(Control *p_base,const Variant& p_data,Control *p_control);
+	void _gui_set_drag_preview(Control *p_base,Control *p_control);
 
 	bool _gui_is_modal_on_top(const Control* p_control);
 	List<Control*>::Element* _gui_show_modal(Control* p_control);