On startup setting values in FlexRepeater

I have a number of checkboxes that are within a FlexRepeater. The instances are created by a script. When the user first loads the view, I want all the checkboxes checked (selected). I am handling this via a delayed onStartup script using sendMessage. This approach works. However, when I navigate away from the view and then return it fails to check all the boxes. I can see the script flash checks into all the boxes, but they don’t “stick”.

Param passing for “selected” is set to bidirectional.