Trying different keys for navigation.

I was having problems with the old scheme.
Now you use tab to switch focus between the summary and result
panes. The keys to navigate are the same in both places.

fill3.py

@@ -354,13 +354,13 @@ class Border:
     THICK = ["━", "━", "┃", "┃", "┏", "┗", "┛", "┓"]
     ROUNDED = ["─", "─", "│", "│", "╭", "╰", "╯", "╮"]
     DOUBLE = ["═", "═", "║", "║", "╔", "╚", "╝", "╗"]
-    HEAVY_INNER = ["▄", "▀", "▐", "▌", "▗", "▝", "▘", "▖"]
-    HEAVY_OUTER = ["▀", "▄", "▌", "▐", "▛", "▙", "▟", "▜"]
-    INNER = ["▁", "▔", "▕", "▏", " ", " ", " ", " "]
 
     def __init__(self, widget, title=None, characters=THIN):
         self.widget = widget
         self.title = title
+        self.set_style(characters)
+
+    def set_style(self, characters):
         (self.top, self.bottom, self.left, self.right, self.top_left,
          self.bottom_left, self.bottom_right, self.top_right) = characters
 
@@ -370,7 +370,11 @@ class Border:
             title_bar = self.top * content_width
         else:
             padded_title = (" " + self.title + " ")[:content_width]
-            title_bar = padded_title.center(content_width, self.top)
+            try:
+                title_bar = padded_title.center(content_width, self.top)
+            except TypeError:
+                padded_title = termstr.TermStr(padded_title)
+                title_bar = padded_title.center(content_width, self.top)
         result = [self.top_left + title_bar + self.top_right]
         result.extend(self.left + line + self.right for line in body_content)
         result.append(self.bottom_left + self.bottom * content_width +