Have a look at this https://zockertown.de/s9y/uploads/linux/schritt2.png
As you can see, the display has only 800x600 resolution. the buttons are covered by the panel.
the solution is shown here:
and here https://zockertown.de/s9y/uploads/linux/schritt3.png
simply move the panel to the right.
But this was done at a last resort. One tries to resize the application window, which is impossible, why?