Why does the updatepanels reload controls outside the updatepanel

Question

I have several UpdatePanels on a page and they have been set with a mode of Conditional. I see a flicker in the controls outside of the UpdatePanels when there is an event that occurs within the UpdatePanel (Say a button click).

The page doesn't post back but the user experiences a "Flicker".

Any idea what might be going on here?

Answer 1

I think you might have got the UpdateMode wrong. By default it is 'Always' if you change it to 'Conditional' it should fix your problem

Answer 2

Do you have event handlers for controls inside the UpdatePanels that make updates to controls outside of the UpdatePanels?

You could try selectively commenting event handlers until it stops flickering to find the culprit.

I also found Firebug to be useful in these cases - you can see the exact HTML going into the updated regions.

Answer 3

You don't say what the callback inside the UpdatePanel is doing.

If it is updating the contents of the panel itself, it could be be the browser is simply repainting the entire page layout to account for the new content just as it would if you resized the browser window.