Step Into

When I access Plato, start a project and step into an application, the display will not open in a full window, even if I minimize and restore the full window, the application display is still not full, as I move down the page, the scroll bar disappears, how do I open the display in a full window?

I am not sure what you mean by the 'display' window. Maybe it is the application view produced by the debugger SDBG. If so then you can start by restoring the default view for SDBG and you can do this by erasing the file called sdbg.ini. This is probably located in C:\Windows.