I'm not sure what is firing this event but in certain cases where you double click or single click the titlebar, the dock will tries to reposition itself again in the dockzone.
In certain extreme cases, it will move to another dockzone.
I would like to remove this behavior from the dock as my layout is fixed.
Thanks.

Hello,

When you "mousedown" on the dock's titlebar (which is fired before "mouseclick") you are actually starting to drag the RadDock, and all of the client-side events related to the dock's movement (OnClientDragStart, OnClientDrag, etc.) are fired. This behavior cannot be changed, but if you want to disable dragging (movement) of the RadDocks you can use the EnableDrag="false".

Let us know if you have other questions.

Regards,
Pero
the Telerik team