This is now implemented. To change please edit the config.json. On windows this is in %appdata%/Papers and in Mac it is located in ~/Library/Application Support/config.json. Open the file in a text editor(Notepad or TextEdit) and change the libraryPageSize to a bigger number. The default is 50.
I would like for the scrolling in lists in the desktop app to work like scrolling should in a desktop app. That means being able to scroll quickly from the top of the library list to the bottom, without it pausing to add items to the list contents over and over again. The web browser interface may have limitations on how many items can be displayed in a list at once, but I don't think this limitation should have carried over to the desktop app. If other users feel differently, then maybe there should be a preference on how many items will be loaded in a list view (50, 100, 500, all, or something like that).
2 people like this idea