Solved
PvZ Free Android: Unable to change plants in Last Stand and Survival modes
Game: Plants vs Zombies FREE (the original game, the 1st one)
OS: Android
There is an issue between the completed flags/days in Last Stand and Survival modes: you are not able to change any of the plants/seeds you selected in first place in Day 1, breaking most of the success you could have being allowed to change them, as picking different seeds for different days as the complexity grows is essential.
OK, I think I have a solution: my mobile device screen has an aspect ratio of 21:9, and I think this generates this problem somehow, as clicking at the left of the seeds effectively unselect them, allowing you to play normally. So if this happens to you, try to click at the left part of the seeds while picking them between flags/days.
