Core Elements 3 engines support manual reload of the page preview, meaning that to see changes made to configuration options, users must trigger a reload of the preview manually. Lightroom will not do it for you.
We use manual reload to speed up the process of working through the Web module. Rather than waiting for the preview to update after every change, every miniscule nudge of a slider, you can adjust multiple items and reload them all at once when you're ready to view the update(s).
There are several ways to enact a reload.
You may enact a page reload by selecting “Reload” from the Web menu:
On LR/Mac, press CMD-R to incite a reload.
On LR/Win, press CTRL-R to force reload.
You can make the button smaller by enabling the “Small Reload Button” checkbox at the top of the Site Info control pane.
A few other actions will also trigger Lightroom to reload the preview.