[BUG] program crashing on particular strings

**Describe the bug** i found this out while using [ncspot](https://github.com/hrkfdn/ncspot), here's the [original issue](https://github.com/hrkfdn/ncspot/issues/1647) raised there. Basically, for particular strings (containing hindi letters, for example) the program just crashes, with the panic message mentioning cursive_core **To Reproduce** this program reproduces the error: ```rust use cursive::views::{Dialog, TextView}; fn main() { // Creates the cursive root - required for every application. let mut siv = cursive::default(); // Creates a dialog with a single "Quit" button siv.add_layer( Dialog::around(TextView::new("मराठी प्रार्थना - Shubham Karoti Kalyanam ")) .title("Cursive") .button("Quit", |s| s.quit()), ); // Starts the event loop. siv.run(); } ``` **Expected behavior** not to crash for any particular string **Environment** * arch linux