Fixed 3D scene mouse capture

xs/src/slic3r/GUI/GLCanvas3D.cpp

@@ -3157,7 +3157,8 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     }
     else if (evt.Dragging() && m_gizmos.is_dragging())
     {
-        m_canvas->CaptureMouse();
+        if (!m_canvas->HasCapture())
+            m_canvas->CaptureMouse();
 
         m_mouse.dragging = true;
         m_gizmos.update(mouse_ray(pos));