The Repeat Content checkbox shows unchecked after clicking on it, as in the screenshot below, while clicking on a readonly checkbox should have no effect. (The box still shows checked after closing the dialog with Apply and reopening the dialog.)
Probably not a regression.
In this case, when the dialog shows, it must create the items of the xf:select[appearance = full]. When doing so, there is no code to set disabled on the HTML input elements if the control is readonly.
xf:select[appearance = full]
Fix #2890 "Section/Grid Settings for repeated grid: can uncheck reado…