With fire spread on, you can attempt to burn items with a flint and steel in the rain. it will take multiple attempts to "burn" the items, but it will happen. Once "burnt" items can still be picked up by the player, as they were never destroyed by the fire.

How to reproduce
1. Turn on dofiretick, set weather to rain.
2. Try to light the ground on fire with a flint and steel (rain should put the fire out)
3. drop an item on the ground, and click on the block below the item with flint and steel.
4. Repeat no.3 until item disappears
5. Once it disappears, stand where the item was and you will pick it up.