Hi Dan Miller,
Yes, the control which is used for "edit" option in SiteFinity is RadWindow.
A simple example which illustrates how to open a RadWindow from another RadWindow is available here:
The RadWindow control wraps an IFrame, and the content is loaded in it. The loading time in RadWindow should be equal as if the content is loaded in IFrame. In case that there is significant time difference, please send us a runnable project, where we can observe it.
the Telerik team
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