If you had followed step by step my scenario, you would have been able to reproduce the bug.
In your video it seems you have refreshed the page before selecting the second item.
The text in the RadCombobox input is ‘Type here …’
I uploaded here
a short video to demonstrate my scenario working.
I added a second scenario that fails at the end of the video.
In fact it seems this issue occurs only for the items in the second half of the last loaded page.
For example if you set up you ComboBox to return 10 items (like it is in your demo page), if you select item 1, 2, 3, 4 or 5 of the list, get_selectedItem()
works and does not return null.
But if you select item 6, 7, 8 or 9 it fails (I was not able to select item 10 without loading the next page (items 11 to 20)).
The key point here is to not trigger the loading of the next page.
If you load it, the items 6, 7, 8, 9 and 10 will work but the items 15, 16, 17, 18 and 19 will fail etc.
To be sure it is not coming from something weird with my computer, I asked a colleague to test this scenario from his side and he got the same issue.