I don't think that you'll have this problem in many of our other controls because the issue is reproducible only in the cases with this structure:
which in not present in all our controls (it can be found in the DropDownButton, SplitButton, DateTimePicker, ColorPicker and maybe a couple more).
As for the ContentControl/ContentPresenter comparison - the ContentPresenter is an element
that is useful inside the template of a ContentControl to specify where you want its content to be placed. It is a lot more lightweighted than the ContentControl (because the ContentControl is a control
and it has a Template, Background and etc. properties that are usual for controls) and also when it Template the Presenter automatically gets its Content, ContentTemplate and ContentSelector so this code:
is equal to this:
And that's why in most cases we use ContentPresenters instead of ContentControls in the Templates of our controls (it's the exact same case with ItemsPresenter and ItemsControl).
We'll consider the problem with the Popup/ContentPresenters and we'll probably fix it for our next release.
I've updated your telerik account and if you have further questions please feel free to ask.
the Telerik team
Explore the entire Telerik portfolio by downloading the Ultimate Collection trial package. Get it now >>