What is Abort for?

I have an uninstall page like,
UninstPage custom un.PagePre un.PageLeave

I have to put "Abort" within PageLeave. Otherwise, if I click anywhere within the uninstall page, then it disappears immediately. Can any one here explain how Abort work here? Thanks.

In a custom page function, abort skips the page. In a page leave function, abort cancels a Next button click (so goes back to the page function).

It sounds like your custom page code is wrong. Please refer to the nsDialogs readme for a tutorial. http://nsis.sourceforge.net/Docs/nsDialogs/Readme.html