This is similar to, and maybe the same issue, as outlined here:
http://www.tasharen.com/forum/index.php?topic=7422.msg35043#msg35043. I'm using 3.0.8 f3; I can update to the latest if you think it will help, but I didn't see anything about this in the change logs.
Basically, when I animate the position of a panel (adjusting it's localPosition) that has a scroll view in it (to move a panel off-screen, for example), the contents of the scroll view will occasionally disappear. If I view the panel in editor after this occurs, I can see that the contents of the panel appear to be missing. The "Draw Call Tool" shows that the panel has "No draw calls found".
I'm finding that three things can potentially fix the issue:
- If you move the contents of the scroll view by dragging it, the contents reappear.
- If I disable the panel before animating it, and then enable the panel, it appears that the contents refresh and show.
- If I adjust the panel's clipping center/size data, the panel contents reappear.
In the case of #3, I find that in script, all that really matters is that mResize be set to true; this seems to recalculate the clipping area and show the panel contents properly. From what I can gather, it seems that maybe moving the scroll view is causing the clipping region to get messed up somehow, which is fixed by forcing a resize event on the panel.
It seems to be a bug to me, but please let me know if I'm doing something wrong as well!