The observed behavior is caused by the fact that the RadToolTip has a bigger z-index than the RadEditor and its dialogs because in most scenarios it is needed that the RadToolTip is above the other controls.
In your particular scenario it is the contrary and you can achieve the desired result by setting a lower z-index to the RadToolTip control. In case you are using the RadToolTipManager you can set it by using its style
attribute as explained here
. Otherwise, if you are using a single RadToolTip control you can use its client-side API in order to apply a proper z-index as shown in the attached demo project.
the Telerik team