Another issue is about "ground plane". When I close and open the file, ground plane disappear. When I click the "ratsnest" button, ground plane apears again. How is "ground plane" made permanent? And how can I switch ground plane off and on for a short time?
1- I could not use "Rip Up" command for removing the track. I closed the eagle pcb without save and opened again. Track (or route mark) disappeared by itself.
2- It is not about the layer settings. Because every layer (top and bottom) has it 's own GND plane. I tried "ripup gnd" command it worked. It deleted inside of the polygon.