Roll20 have chose to handle spell selection that way for divine spellcaster, due to how adding all the spells to a sheet would slow it down.(It's also the reason why NPC spellcasters don't automatically have all the spells prepared, but are only listed for efficiency's sake) So select two spells your character prepares for the day, and after the levelup or next time you prepare your spells, you can add new spells to the sheet as you use them, but the general advice is to add only spells you use to the sheet. Drag-n-drop spells from the compendium afterwards is pretty quick if you decide to prep a spell that isn't already on your sheet. I guess it would be useful to have an optional field for divine spellcaster where you could save the name of all the spells on your spell list, to more easily go through all your options. You could add a link to the compendium entry that lists all the paladin spells on some spot on you character's notes for easy access to the list, of nothing else. You can ask your GM for making a duplicate of your character and try adding all the lvl.1 & lvl.2 spells to it and see if you notice a large slowdown. It's possible that isn't a problem yet, and that it's more of an issue with clerics/druid or high-level paladins that would have a ton of spells.
