If a scrollbar is contained in the content of a RadCallout, clicking the scrollbar thumb will close it. An example of this is with a RadListBox, where clicking a RadListBoxItem will not close the callout, but clicking the vertical scrollbar will close it.

Placement, VerticalOffset and HorizontalOffset settings are not respected when CanPopupExceedScreen is True and Placement is other than Left/Right/Top/Bottom.
The callout is shown at the (0,0) position of the target control with these settings.
Exected: Placement, Vertical and horizontal offsets are properly respected and callout is positioned according to them.

The callout gets clipped when the Content property is null and the ContentTemplate is set, as well as the arrow points are set to custom values.

The workaround for this is to set the Content property.

Show/Close animation duration is still executed when the show/close animation type is None

If you define a custom ContentTemplate with a TextBlock element inside of it and then set the TextTrimming or TextWrapping property of the TextBlokc, the value is not respected. Instead, the default TextTrimming/TextWrapping from the RadCallout control is used. 

Note that this happens only for the first TextBlock in the template.

To resolve this, use the TextTrimming and TextWrapping properties of RadCallout. Or alternatively, define an empty TextBlock in the template and add another TextBlock for the text after that.