void DockManager_OnPaneDragOver(object sender, PaneDragOverEventArgs e) { if (e.DragAction.GetType() != typeof(MoveWindowAction)) { var contentPane = e.Panes[0]; MainViewModel mainViewModel = DataContext as MainViewModel; if (mainViewModel != null && contentPane != null) { var windows = Application.Current.Windows; foreach (var window in windows) { var actuallWindow = window as Window; if (actuallWindow != null) { var windowType = actuallWindow.GetType(); if (windowType.FullName == "Infragistics.Windows.Controls.ToolWindowHostWindow") { WorkflowDesignerViewModel workflowDesignerViewModel = contentPane.TabHeader as WorkflowDesignerViewModel; if (workflowDesignerViewModel != null && contentPane.ContentVisibility == Visibility.Visible) { PaneDragAction paneDragAction = e.DragAction; if (paneDragAction is AddToGroupAction || paneDragAction is NewSplitPaneAction || paneDragAction is NewTabGroupAction) { e.IsValidDragAction = false; e.Cursor = Cursors.No; } } } } } } } }