First I would like to explain a bit about the RepeatColumns
property. Its purpose is to divide the RadMenu items equally between the number of columns.
From the attached image I can see that there are 5 items altogether. In order to divide 5 items between 3 columns the items should be ordered as follows: two for the first column, two for the second and 1 for the last one.
In this case having only one item in first and second column and placing the rest of the items in the third column is not supported scenario using the RepeatColumns
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