C# application maximized window -

first resize window button doesn't want work ,for reason.

private void fullscreenbutton_click(object sender, eventargs e)     {         if (this.windowstate == formwindowstate.normal)         {             this.windowstate = formwindowstate.maximized;         }         if (this.windowstate==formwindowstate.maximized)         {             this.windowstate = formwindowstate.normal;         }     } 

and if make form maximized vs form properties http://postimg.org/image/mmy9r7qu9/ ,the form turns http://postimg.org/image/kzeyrb9fb/ .what going on?

1. click on form
2. go it's properties
3. find option: "windowstate"
4. change "maximized"

you can see image option in: https://www.mediafire.com/view/nmnf8wcjsl1zi6z/windowstate.bmp

and can try "button_click":

private void fullscreenbutton_click(object sender, eventargs e) {     if (this.windowstate == formwindowstate.normal)     {         this.windowstate = formwindowstate.maximized;     }     else     {         this.windowstate = formwindowstate.normal;     } }