bootstrap 4 - adding items to IWBS4Select

[bostjan]

Hi,

I ran into new problem while trying to convert to Bootstrap 4.
I have a combo box TIWBS4Select with some items and I would like to add some more - I put a button and with a click on that button I want to add one more item:

Code:

IWBS4Select1.Items.Add('new 1');

When I run the program in this line I'm getting an error: 'access violation at adress xxxxxx'. What is the correct way of adding items?

Kind regards,
Bostjan