Flash Form Cell Renderer Weirdness

I recently had to revisit my Flash Form combobox cell renderer examples to use the technique in a project that I am working on and found a very weird behavior that I'm hoping someone can help me figure out. Here is what's happening: When using a custom cell renderer in conjunction with an editable grid that allows row inserts, when the rows extend beyond the visible height of the grid, the combobox renderers begin to act very weird. Go to the example below and add about 15-20 rows and you'll see what I mean. After adding the rows, scroll up and down in the grid and things will just keep changing. Anyone know what's up? I am a little concerned that this is one of the drawbacks to hacking up this solution, but there really is no difference in this technique than techniques employed in Flex (which is really what Flash Forms are).

Example