wxLB_EXTENDED not working with wxListBox

I am having a really weird problem. In my program I am using a tab widget and two pages on that tab widget. Both pages contain a wxListBox widget on them. I am using wxLB_EXTENDED with both of the List boxes.

The problem is that the the ListBox on first page is working accordingly and I am able to select multiple items. But the ListBox on the second page is only selecting Single item from the list. All the configurations for both the ListBoxes are same and I dont know what is the issue.

Any help would be appreciated.

Mohsin