Some cleanups for ubl lcd mesh map

Marlin/Conditionals_LCD.h

     #define LCD_FEEDRATE_CHAR    0x06
     #define LCD_CLOCK_CHAR       0x07
     #define LCD_STR_ARROW_RIGHT ">"  /* from the default character set */
+
+    #if ENABLED(AUTO_BED_LEVELING_UBL)
+      #define LCD_UBL_BOXTOP_CHAR 0x01
+      #define LCD_UBL_BOXBOT_CHAR 0x02
+    #endif
+
   #endif
 
   /**

Marlin/ultralcd.cpp

 
     void _lcd_ubl_output_map_lcd() {
       static int16_t step_scaler = 0;
-      int32_t signed_enc_pos;
 
-      defer_return_to_status = true;
-
-      if (axis_known_position[X_AXIS] && axis_known_position[Y_AXIS] && axis_known_position[Z_AXIS]) {
+      if (!(axis_known_position[X_AXIS] && axis_known_position[Y_AXIS] && axis_known_position[Z_AXIS]))
+        return lcd_goto_screen(_lcd_ubl_map_homing);
 
-        if (lcd_clicked) { return _lcd_ubl_map_lcd_edit_cmd(); }
+        if (lcd_clicked) return _lcd_ubl_map_lcd_edit_cmd();
         ENCODER_DIRECTION_NORMAL();
 
         if (encoderPosition) {
-          signed_enc_pos = (int32_t)encoderPosition;
-          step_scaler += signed_enc_pos;
+          step_scaler += (int32_t)encoderPosition;
           x_plot += step_scaler / (ENCODER_STEPS_PER_MENU_ITEM);
           if (abs(step_scaler) >= ENCODER_STEPS_PER_MENU_ITEM)
             step_scaler = 0;
           refresh_cmd_timeout();
 
+          encoderPosition = 0;
           lcdDrawUpdate = LCDVIEW_REDRAW_NOW;
         }
 
-        encoderPosition = 0;
-
         // Encoder to the right (++)
         if (x_plot >= GRID_MAX_POINTS_X) { x_plot = 0; y_plot++; }
         if (y_plot >= GRID_MAX_POINTS_Y) y_plot = 0;
 
           ubl_map_move_to_xy(); // Move to current location
 
-          if (planner.movesplanned() > 1) { // if the nozzle is moving, cancel the move.  There is a new location
-            #define ENABLE_STEPPER_DRIVER_INTERRUPT()  SBI(TIMSK1, OCIE1A)
-            #define DISABLE_STEPPER_DRIVER_INTERRUPT() CBI(TIMSK1, OCIE1A)
-            DISABLE_STEPPER_DRIVER_INTERRUPT();
-            while (planner.blocks_queued()) planner.discard_current_block();
-            stepper.current_block = NULL;
-            planner.clear_block_buffer_runtime();
-            ENABLE_STEPPER_DRIVER_INTERRUPT();
-            set_current_from_steppers_for_axis(ALL_AXES);
-            sync_plan_position();
+          if (planner.movesplanned() > 1) { // if the nozzle is moving, cancel the move. There is a new location
+            quickstop_stepper();
             ubl_map_move_to_xy(); // Move to new location
           }
         }
-        safe_delay(10);
-      }
-      else lcd_goto_screen(_lcd_ubl_map_homing);
     }
 
     /**

Marlin/ultralcd_impl_HD44780.h

           B00000,
           B11111
         };
-        createChar_P(1, _lcd_box_top);
-        createChar_P(2, _lcd_box_bottom);
+        createChar_P(LCD_UBL_BOXTOP_CHAR, _lcd_box_top);
+        createChar_P(LCD_UBL_BOXBOT_CHAR, _lcd_box_bottom);
       #endif
     }
 
          * Draw the Mesh Map Box
          */
         uint8_t m;
-        lcd.setCursor(_MAP_X, 0); for (m = 0; m < 5; m++) lcd.write(1); // Top
-        lcd.setCursor(_MAP_X, 3); for (m = 0; m < 5; m++) lcd.write(2); // Bottom
+        lcd.setCursor(_MAP_X, 0); for (m = 0; m < 5; m++) lcd.write(LCD_UBL_BOXTOP_CHAR); // Top
+        lcd.setCursor(_MAP_X, 3); for (m = 0; m < 5; m++) lcd.write(LCD_UBL_BOXBOT_CHAR); // Bottom
         for (m = 0; m <= 3; m++) {
           lcd.setCursor(2, m); lcd.write('|'); // Left
           lcd.setCursor(8, m); lcd.write('|'); // Right