Thank you for your question.
The closing events are fired in the following order:
FormClosing of the form
FormClosed of the form
DockWindowClosing of the DockWindow that hosts your form
DockWindowClosed of the DockWindow that hosts your form.
So, in order to achieve your scenario, you should implement your logic in the FormClosing event handler of the form.
I hope that this information helps. If you have additional questions, feel free to contact me.
the Telerik team
Q1’11 SP1 of RadControls for WinForms is available for download
; also available is the Q2'11 Roadmap
for Telerik Windows Forms controls.