Item Count in Tab Name

I just wanted to know why if you messed up that detail in the script, it's my PC that has a problem because when copying, pasting, creating new documents, etc., it doesn't update the number of these

The link I have posted leads to the explanation. Would you mind reading it?

Surely yes, I'm going to read it right now, thank you very much!

Thanks @lxp for confirming my suspicion.