Specifies whether width of the popup list box should fit list items.
property AutoSize: Boolean;
Set AutoSize to True to enable automatic width calculation of the popup list to fit all items it it.
When autosizing is enabled before showing auto-complete popup list all items have to be parsed to calculate width of list. This may cause showing delay.
For large number of items (thousand and more) it is recommended to disable auto-sizing and to disable column mode (WithColumns property).