Thank you for reporting this appearance glitch.
The problem is due to that the Cancel button of the Image Manager (opened via Properties dialog) sets the focus in the content area which shows the ShowOnFocus toolbar over the Properties dialog. The correct behavior is to set the cursor in the Properties dialog inside the Image Src field when the Image Manager dialog is closed.
I logged the problem in our PITS system and we will fix it in a future build of RadEditor. I also updated your Telerik points. Here you can find the PITS Issue: Public URL
Currently, you can chose either the PageTop
or Default ToolbarModes
the Telerik team
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