[input] Reset cursor position on focus change.

input.lua

@@ -126,16 +126,23 @@ end
 
 function Input:keyreleased(key)
     if self.candidate.length == 0 then
+        local moveTo
+
         if key == 'home' then
             self.cursor = 1
         elseif key == 'end' then
             self.cursor = utf8.len(self.text)+1
         elseif key == 'up' or key == 'down' then
-            self.ui:navigate(key)
+            moveTo = key
         elseif key == 'tab' or key == 'return' then
-            self.ui:navigate('right')
+            moveTo = 'right'
         elseif key == 'escape' then
-            self.ui:navigate('cancel')
+            moveTo = 'cancel'
+        end
+
+        if moveTo then
+            self.cursor = 1  -- reset cursor position
+            self.ui:navigate(moveTo)
         end
     end
 end