Question

Is there a way to make the <Return> event call on the key release, instead of press?

If you use <KeyRelease>, then event.char is blank for any special key, not just return.

Answer 1

You can explicitly set a binding on the release of the return key by binding to <KeyRelease-Return>.

For example:

import Tkinter as tk

class SampleApp(tk.Tk):
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)
        self.text = tk.Text(self)
        self.text.pack()
        self.text.bind("<KeyRelease-Return>", self.on_return_release)

    def on_return_release(self, event):
        self.text.insert("end", "boink! ")

if __name__ == "__main__":
    app = SampleApp()
    app.mainloop()

If you don’t want anything to happen on a press of the return key you can remove the default binding, or create your own binding which returns "break"