I don't recall ever having this issue for me in the past, ever. i know that this issue has been around for some people for years. anyway i use Terraria on steam and when i got a brand new desktop i had to redo my key binding. for example "ESC" is the key to open the inventory/menu. i prefer "TAB" as well as other things to accommodate my preferences. No matter what i do, if i click or select a command to be changed it will change to "nothing". then it will immediately disable my left mouse click function. so i can't click that "go back" button on the menu, or even select any other commands to change let alone reverse or fix the command i just attempted to change. i found that pressing the windows key on my key board and then clicking back into the game's window, will re-enable the left mouse click function ONLY if i choose to "go back" out of the key binding menu. if i try to select a command to change it will repeat the process of me trying to change a command and it will select it as it turns the command yellow and then, interestingly enough NO MATTER WHAT BUTTON (Both Console Controllers X1/PS4) OR KEY I PRESS CHANGES IT TO 'NOTHING". this is such a basic and IMHO an important issue that needs to be addressed i can understand bugs and stuff with this game IN GAME especially with new patches or hot fix's release but this feels ridiculous. I would sincerely appreciate any help for a fix i have searched high and low. i tried to reset the .ini or .json file (whichever it's called) by deleting it. also i saw someone said they had this issue 3 years ago but only in window mode and coincidentally i was using window mode but that also didn't fix it. i dont know what else to do any way thats all.