[JimmXinu]

Okay, I think I have this figured out. I was tired last night and making assumptions based on the way I use Reading Lists, which is different than you do.

For future reference, this discussion started in SmartEject:

Originally Posted by ownedbycats

I installed SmartEject for the reading-list sync (and having a giant eject button on the toolbar). However I noticed that it always reminds me that there's books to be synced even when there's not. When I press "yes" the device doesn't eject (perhaps it's waiting for the nonexistent sync job to finish?).

I have one list per device I keep sync'ed and use FFF to automatically add new/updated books to those lists. I use 'Add/overwrite all list items to device' (to make sure that updated FFF stories are written to device even if already there) with 'Clear this list after a sync to this device' checked (to only send them once). It works great with Smart Eject--no surprise, since I made Smart Eject to work that way.

Reading List determines if there are lists that could be sync'ed (aka Sync Now is enabled) only by looking at whether there are entries in lists configured to sync the attached device. It does not take into account the distinction between 'New items' and old items.

Only when you actually do 'Sync Now' does RL compare the current contents of the device to the list and figure out which are 'new' (aka not on the device) and which are already on the device and can be skipped.

Whether that's because of historical reasons, or performance reasons, I couldn't tell you. But it looks like RL's Sync is functioning as designed.

I hesitate to try changing the need-to-sync check to include checking the device. I don't know why it works like it does now. My guess is performance--the Sync Now enabled/disabled check is done every time any list is changed in any way.