All RadControls' popups have a default z-index style:
In order to change the z-index of the popup RadCalendar (when it is part of a RadDatePicker control), you can use the picker's ZIndex property and set a large-enough value (depending on the z-index of the other popup).
If you are using an older RadControls version, the ZIndex property may not be available. In this case, please use some of the alternative techniques:
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