simple crash:

lnbDeleteColumn [-1]

^^^^ passing array that is shorter than size 2

more sophisticated crash:

• spawn {

with uiNamespace do {

		lnb = findDisplay 46 ctrlCreate ["RscListNBox", -1];
		lnb ctrlSetPosition [0,0,1,1];
		lnb ctrlCommit 0;
		hint str lnbGetColumnsPosition lnb;

};
for "_i" from 1 to 3 do {

		sleep 2;
		with uiNamespace do {
			lnb lnbDeleteColumn 0;
			hint str lnbGetColumnsPosition lnb;
		};

};
};

^^^^^^^^^^^ deleting last column causes crash

+related crash, related to deleting of the columns, as it will be resizing columns array:

with uiNamespace do {
lnb = findDisplay 46 ctrlCreate ["RscListNBox", -1];
lnb lnbSetColumnsPos [];
};

As it happens, creating LNB control in description.ext with columns[] = {}; and then trying to display it will also cause a crash. It seems no matter what LNB doesn't like to have no columns.