Extending the mobile RadMenu capabilities depends on the feedback received from customers.
I have logged a Mobile RadMenu Feature Request
for a visual indicator which suggests to users that the expanded menu is scrollable. You may vote for it, comment it and track its status by clicking the "Follow this item" button.
As for the height property not set and the EnableAutoScroll="true" issues you mention, unfortunately, I am not able to reproduce that behavior on my side. You may check if you are setting menu height for mobile devices. Probably you have some logic in the code behind for Small and Medium ranges that sets height. On my side, the root menu always expands to show all root items and cannot be scrolled - tested on iOS Safari and Chrome, as well as Android Chrome browser.
And last, but not least, you may use the RadDeviceDetectionFramework
and the ScreenSize information it provides, to set different dimensions and other properties you would like for different screen size ranges. It would enable you to achieve a custom layout for Small, Medium, Large screen devices, or even for ScreenSize ranges you would like to set by yourself.
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