There is a problem with the margins display in current versions of WebEasy. If you have margins turned on then scroll up and down your page for a while, WebEasy may crash - this is likely the source of your problem.
1) Open your site in WebEasy.
2) Go to the "Tools" menu and select "Options".
3) Select the "Grid" tab.
4) Un-check the "Display Web Page margins" box.
5) Click OK.
6) Save your site and close it to make sure turning the margins off takes effect.