@Override
	public boolean isInsertAllowed(int currentIndex, DataType datatype) {
		if (currentIndex > getNumComponents()) {
			return false;
		}
		return true;
	}
Returns whether or not insertion of the specified component is allowed
at the specified index.

@param currentIndex index of the component in the structure.
@param datatype the data type to be inserted.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/compositeeditor/StructureEditorModel.java