0025622: Problem with display logic in grid for buttons when those are using auxiliar inputs containing null values

diff -r 368bed7f2e19 modules/org.openbravo.client.application/web/org.openbravo.client.application/js/toolbar/ob-action-button.js
--- a/modules/org.openbravo.client.application/web/org.openbravo.client.application/js/toolbar/ob-action-button.js	Thu Jan 09 06:18:37 2014 +0100
+++ b/modules/org.openbravo.client.application/web/org.openbravo.client.application/js/toolbar/ob-action-button.js	Fri Jan 31 11:19:04 2014 +0100
@@ -252,6 +252,7 @@
 
     if (!multiSelect) {
       OB.Utilities.fixNull250(currentValues);
+      OB.Utilities.fixNull250(context);
 
       this.visible = !this.displayIf || (context && this.displayIf(this.contextView.viewForm, currentValues, context));
       readonly = this.readOnlyIf && context && this.readOnlyIf(this.contextView.viewForm, currentValues, context);