I'm trying to open a `SitePage` in a Dialog. I currently arranged it for a `Form` of a ListItem, but when I apply the same code to a `SitePage` I get the following correlation error:

> 
> An exception occurred while rendering the Ribbon on the SharePoint Page.  
> 
>  The following exception was thrown : System.ArgumentException:   
> 
>  The Ribbon Tab with id: "Ribbon.Read" has not been made available for   
> 
>  this page or does not exist. Use Ribbon.MakeTabAvailable(). 
> 
> 
> 

My JavaScript code:

```
var dialogOptions = SP.UI.$create_DialogOptions();
dialogOptions.url = '../myPage.aspx?Leistung=MyParam';
SP.UI.ModalDialog.showModalDialog(dialogOptions);

```

I also tryied to add the param `IsDlg=1`, same error.
Note that if I manually open the Url in the browser it works.