[Unsolved]Cannot get the next selectable item during compile time

Hello

I am attempting to insert buttons into a list with this script that runs on Start() Note that the buttons navigation is set to automatic.

Code (CSharp):

1. Selectable potentialButton = firstButton;
2. while (true)
3.     {
4.       if (potentialButton == null)
5.          {
6.             Debug.Log("button is null");
7.             break;
8.          }
9.       if (IsValidButton(potentialButton))
10.       {
11.          TopRow.Add((Button)potentialButton);
12.          potentialButton = potentialButton.FindSelectableOnRight() as Button;
13.  
14.       }
15.    }

However it doesn't seem to be adding the buttons properly. Matter of fact, the number of items in the TopRow list seems to be random. However when I run that same command during runtime, I am getting the correct number of elements inserted into the list. This is strange behaviour, how do I go about correcting this?