Calunio, finally i think all those issues are solved now.
The problem was in fact the event triggering with the space or "z" keys. That+s fixed in latest patch (v 1.1.3.)
Viewing post in Player Text Input Plugin [RPG Maker MV +MZ] comments
Thank you! It seems to be working now! Sadly for you, I'm a pretty good bug hunter hahaha. I found a bug that probably not a big deal, but you never know. I was testing with keys and typing texts, when it reached a point where each time I typed a letter it would give me 3 of them. Like II aamm ttyyppiinngg nnooww. I try to replicate the bug, and eventually I did that by interacting with the event and holding the Enter button. It would quickly skipe the input, but next time it gave me double letters. I also came across moments when one key stopped working and I had to press another to interact with the event, but I'm not sure what caused it. Anyway, I feel like the fact that multiple keys can be used to activate the plugin is an issue. In any case, this might be something to ignore. I'll keep in touch in case anything serious comes up when I'm using it in my game.
Whoa you're the best tester ever sir.
I never got to those bugs but i'll try to reproduce them myself. The event triggering with multiple keys was an issue but i think that part is solved now. The bugs you're encountering are probably due to the the logic behind managing the window within the scene and making the game understand where it is at each moment.
Will keep working on it and keep you posted