When selecting a new script in the listview, we now properly update the textboxes for the selected script instead of the first entry in the listview. In addition, we no longer always update the first item in the listview to contain the properties of the selected script.
Produce an error when SmartScriptListView.SelectedSmartScript returns null -> it will cause errors which are hard to backtrace (it should never be happening..)
When checking or unchecking the 'Show basic information' checkbox, we now re-select the last selected script (if any) afterwards
Fix an issue where the Show Basic Information would be completely ignored when adding a new line to your script