Script Manager Sorting Question

There appears to be some row focus issues when sorting a script position within the script manager. It is exhibiting unexpected behaviors. See this video for a sort illustration.

Also, I have triggered an exception within an array that I am guessing is used to hold attributes of the script manager sort / row position. It was an index out of bounds. It was not a fatal exception. Will see if I can flush it out of the weeds again...

Just curious, Is the script manager's collection mechanism/container an array or custom class?