>Set refresh to 1 means to refresh every grid every second!!! With many records your grids won't even have the time to refresh before another refresh is called. I suggest that you set this to 0 and instead add a button to refresh the grid(s), if it's necessary at all.
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AFAIK Grids are not affected by the setting of REFRESH. Browses are but they have no biss. in an app.