Photo_Editor_Application.PhotoEditorForm.RectangleButton_Click Function
Sets the selected tool to RactangleTool if no tool was selected before. If a tool was selected before then the tool selection is reset to no tool.

Private void RectangleButton_Click (object, System.EventArgs)
  Type Name Description  
    object sender Object that sent the event.  
    System.EventArgs e Parameters provided by the event.  
  Return Description  
    void