#523 Color code background for thumbnails that were created since last scan action

[Adam Smith]

Request: Add a colored background to all thumbnails that were created since the last scan action was started.

Document scanner hardware isn't perfect so sometimes a stack of papers will get stuck on a particular sheet, pull multiple sheet through simultaneously, or some such error. In such a case the user may want to quickly remove all pages that were created since the last button press and then redo the whole stack. That would be easier if NAPS2 visually marked which pages were part of the last scan action.

Example: The user has already scanned 100 pages. Batch mode is now started on another batch of 20 pages. After a few pages the scanner feeder mechanism pulls in the whole remaining stack in one go and gets stuck midway.

To undo that error the user currently has to carefully check

• which pages in the stack were scanned correctly (and keep them) during the last action
• which pages in the stack were scanned incorrectly for example only half of the page got scanned during the last action (and delete them)
• which pages in the stack were not scanned during the last action

It would in many cases be much quicker to simply delete all pages created by the last action and after that redo that whole stack if the thumbnails for pages created by the last action had a visual cue such as a special background color.

A button or shortcut to directly select and delete all pages created by the last action would be even quicker. But that has the risk of users accidentally triggering the button/shortcut. A background color is useful enough and has no such accident risk.