Show dialog on custom ribbon button

Created a custom ribbon button on case entity and on click of button show a dialog. on completion of dialog refresh entity form.
....
<CustomAction Id="NewCancel" Location="Mscrm.Form.incident.MainTab.Actions.Controls._children">
            <CommandUIDefinition>
              <Button Id="NewCancelButton" ToolTipTitle="$Resources:Ribbon.Form.incident.MainTab.Actions.Cancel" ToolTipDescription="$Resources:Ribbon.Tooltip.CancelCase" Command=AbandonCase" Sequence="6" Alt="$Resources:Ribbon.Form.incident.MainTab.Actions.Cancel" LabelText="Abandon Case" Image16by16="/_imgs/ribbon/CaseCancel_16.png" Image32by32="/_imgs/ribbon/CancelIncident32.png" TemplateAlias="o1" />
            </CommandUIDefinition>
          </CustomAction>

....

<CommandDefinition Id="AbandonCase">
            <EnableRules>
              <EnableRule Id="IsExisting" />
            </EnableRules>
            <DisplayRules />
            <Actions>
              <JavaScriptFunction FunctionName="AbandonCase" Library="$webresource:new_incident.js" />
            </Actions>
          </CommandDefinition>

then created a javascript function to show dialog when user click on the custom button


AbandonCase = function () {
    window.showModalDialog(OrganisationPath + "/cs/dialog/rundialog.aspx?DialogId=" + AbandonCaseDialog + "&EntityName=incident&ObjectId=" + Xrm.Page.data.entity.getId());
    refreshEntityForm();
}



refreshEntityForm = function()
{
  //used mainly from ribbon buttons

  if (Xrm.Page.data.entity.getIsDirty())
  {
      // Save form - causes reload
      Xrm.Page.data.entity.save();
  }
  else
  {
     // Reload form.
      window.location.reload(true);
  }
}