set_modal
Description:
Sets whether the file chooser dialog blocks interaction with the parent window while it is presented.
Parameters:
| this | 
           a file dialog  | 
      
| modal | 
           the new value  | 
      
Sets whether the file chooser dialog blocks interaction with the parent window while it is presented.
| this | 
           a file dialog  | 
      
| modal | 
           the new value  |