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.
Solution
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.