By design, when RadEditor's ToolbarMode property is set to ShowOnFocus you need to click inside the content area to display the toolbar, and click on the page to hide it - the functions that toggle visibility of the toolbar are assigned as handlers to the "click" event.
I will log this scenario in our ToDo list for further investigation and we will do our best to handle it for one of the upcoming releases. However, I am unable to provide a firm estimate. I will bookmark this ticket and will write back to you as soon as we have any suitable workaround.
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