Attached is a simple test program that demonstrates the problem. The app has a ToolStripEx and a DockingManager that adds a panel. When you end the app normally by clicking the close button (X) the app will crash with "Object reference not set to an instance of an object" inside Syncfusion.Windows.Forms.Tools.DockHostController.get_LayoutRect(). This happens during the call to components.Dispose(). If you remove the ToolStripEx then the problem does not happen. There seems to be an issue with the interaction between the 2 controls.
Attachment:
test_4c89d858.zip