Export PDF options behaviour can lead to accidentally triggering a full space export

Reproducible using Chrome 38 and Confluence 5.6.3.

When you use the browser "back" button to return to the Export PDF Options page after doing a custom export of selected pages, it remembers that you had selected "Custom Export" but the page selector is reset to the default of "all pages" and the page selection is not displayed. (see back to export pdf options.png) A user may then click on the Export button, either in an attempt to get the page list to be displayed, or on the assumption that the same page selection will be used as last time. This triggers an accidental full space export which consumes resources needlessly.

Workaround is to click on Custom Export or change the export type to Normal Export and then back to Custom, so that the page selection is displayed and the user can set the pages to export (again).

Note that the behaviour is different with Firefox 31 ESR. In that case when you go "back" to the Export PDF Options page after doing a custom export of selected pages, all selections are reset to initial values. This means that the type is set back to Normal Export. It's not nice that the user's settings have been forgotten, but at least they are all forgotten consistently and it's unlikely that the user will be confused about what will happen when they click Export.

What would really be nice is if the tool remembered all the export settings (export type and selected pages) so that a user could easily redo the same export. One of our users discovered this problem when they did a custom export, checked the results, discovered a problem, fixed it on the Confluence page, and then tried to go "back" to redo the same export.