During the start of the game, when you enter the shop for the first time. The 'tutorial' which is used to explain purchasing will block the 'left arrow' meaning if you click the right arrow before buying the Guarden Plant as required. You will be unable to go back and choose it, refreshing the game is the ONLY way to recover this as far as I could see.

Hello. This is definitely not working as intended, I'll fix it in the next patch. In the meantime, there is a way to get out of that lock–if you continue to click the right arrow you'll cycle back around to the first window. Thanks for reporting