In NetBeans v8.2 Alt+Enter shortcut doesn't work on Windows 10 x64 OS on my computer, but in the same version of NB on Ubuntu 16.04 on my computer, it does... 
For example, if I write a code something like this:

import java.util.List;         // This line will be yellow under-lined, and normally if I press Alt+Enter
                                        // A popup menu will appear and say "Remove unused import"
                                        // But that popup menu doesn't appear and not for this for every hints

public class DenemeProje {
    public static void main(String[] args) {
        
    }
}


If I go to Tools>Options>Keymaps and change Alt+ENTER to anything else, for example Alt+E, it does work, also Ctrl+ENTER or Ctrl+Shift+ENTER or Alt+Shift+ENTER operations are working properly, only problem is Alt+ENTER...
So I can't see hints on Windows. Please help me for solving this problem.