Associating a tk.StringVar with CTkEntry erases placeholder text

Hello.

I have added StringVar to CTkEntry widget, using the textvariable parameter. I am then binding the key release event to a function. The idea being that as the user types, the characters are converted to uppercase:

        self.tk_new_db_account_name = tk.StringVar(master=self.frm_new_entry)
        self.ent_new_db_account_name = ctk.CTkEntry(master=self.frm_new_entry,
                                                    placeholder_text='Database username',
                                                    textvariable=self.tk_new_db_account_name)
        self.ent_new_db_account_name.grid(row=row, column=0, padx=default_padx, pady=default_pady)
        self.ent_new_db_account_name.bind("<KeyRelease>", self.db_account_caps)

In case it is relevant (unlikely), db_account_caps method looks like this:

    def db_account_caps(self, event):
        self.tk_new_db_account_name .set(self.tk_new_db_account_name .get().upper())

The capitalisation works, however this causes the 'Database username', placeholder text, to be ignored (or erased). If I remove the StringVar, the placeholder text reappears.

This is happening with CustomTkinter 4.6.3.

Is this a bug or am I missing something?

Thanks.

Start by reproducing the CTkEntry example in CustomTkinter 4.6.3 with both textvariable and placeholder_text, then compare it with the version without StringVar. Check whether the placeholder remains visible while the KeyRelease callback uppercases the value; done means both behaviors work together.