Question

I have a (second) tkinter window, which, when opened, does not get the focus, but rather the first window remains focused (although the second window appears in front of the other).
It contains a textbox which I want to be able to type in, but I have to double-click it in order to type.

How do I focus the textbox when opening the window?

My tries:
textbox.focus_set(),
window.grab_set(),
window.focus_set()

None of them did what I wanted to do.

EDIT:
Instead, .focus_set() raises an error when (and only when) closing the main window: can't invoke "focus" command: application has been destroyed

This is my current code (tkWin is the main window, tkcWinis the second window):

def click(self, field):
    import _tkinter
    if field != None:
        try:
            self.tkcWin = Tk()#creating window
            self.tkcWin.focus()
            self.tkcWin.title(field)
            self.tkcWin.geometry('300x100')
            self.mainframe = Frame(master=self.tkcWin,background="#60BF98")
            self.mainframe.place(x=0, y=0, width=300, height=300)
            self.textb = Text(master=self.mainframe)
            self.textb.place(x=0, y=50)
            self.textb.bind("<Return>",lambda a: self.setM(field))
            self.textb.bind("<Return>",lambda a: self.tkcWin.destroy(),True)
            self.tkcWin.grab_set()
            self.tkWin.wait_window(self.tkcWin)
            self.textb.focus_set()
            hwnd = self.tkcWin.winfo_id()
            ctypes.windll.user32.SetFocus(hwnd)
            self.tkcWin.mainloop()
        except _tkinter.TclError:
            self.tkcWin.destroy()

Answer 1

It turns out that you can simply call the secondary window’s deiconify() method and then the widget’s focus_set() method:

toplevel.deiconify()
text.focus_set()

---

Here’s the original work-around for Windows (no longer recommended):

Start by adding import ctypes at the top.
Go ahead and focus your widget like you have with: text.focus_set()
Get the hwnd of the second window: top_hwnd = toplevel.winfo_id()
And finally activate the second window with: ctypes.windll.user32.SetFocus(top_hwnd)