Just to rule out something simple, it looks like you don't have an action currently in that screen shot. To the left of the red triangle for a bonus action there would be a green circle if you had an action, and since you're in turn based mode it means you wouldn't be able to cast any spell.
Having said that, I don't know why it is saying that Chromatic Orb isn't prepared when it clearly is in your spellbook.
The little ticks are the spells you have had Gale prepare, if you check all of the spells with the tick they are the ones that are also in the prepared section.
