Since performance doesn't matter here, always update widget state

It shows that we really want to just have persistent widgets to keep
their own state, but then... we can't share the application state
anymore. Maybe that was never the best idea...

src/interactive/app.rs

@@ -68,7 +68,7 @@ enum CursorDirection {
 }
 
 impl TerminalApp {
-    fn draw<B>(&mut self, terminal: &mut Terminal<B>, do_update: bool) -> Result<(), Error>
+    fn draw<B>(&mut self, terminal: &mut Terminal<B>) -> Result<(), Error>
     where
         B: Backend,
     {
@@ -81,16 +81,14 @@ impl TerminalApp {
 
         terminal.draw(|mut f| {
             let full_screen = f.size();
-            let mut window = MainWindow {
+            MainWindow {
                 traversal,
                 display: *display,
                 state: &state,
                 widgets,
-            };
-            if do_update {
-                window.update();
             }
-            window.render(&mut f, full_screen)
+            .update()
+            .render(&mut f, full_screen)
         })?;
 
         Ok(())
@@ -106,7 +104,7 @@ impl TerminalApp {
     {
         use termion::event::Key::{Char, Ctrl};
 
-        self.draw(terminal, false)?;
+        self.draw(terminal)?;
         for key in keys.filter_map(Result::ok) {
             match key {
                 Char('O') => self.open_that(),
@@ -120,7 +118,7 @@ impl TerminalApp {
                 Ctrl('c') | Char('q') => break,
                 _ => {}
             };
-            self.draw(terminal, true)?;
+            self.draw(terminal)?;
         }
         Ok(WalkResult {
             num_errors: self.traversal.io_errors,