Fixed input control in balancing mode.

app/models/article_price.rb

@@ -16,6 +16,8 @@ class ArticlePrice < ActiveRecord::Base
   belongs_to :article
   has_many :order_articles
 
+  validates_presence_of :price, :tax, :deposit, :unit_quantity
+  
   # Custom attribute setter that accepts decimal numbers using localized decimal separator.
   def price=(price)
     self[:price] = String.delocalized_decimal(price)