I'm upgrading my mod from 1.9 to 1.15.2 which involves quite a lot of differences, and I'm having trouble getting my custom GUI to render. I've got keybinds working so it displays the gui, which I can tell because it displays the cursor ready for interaction, but the gui isn't being rendered so it's completely transparent. Any idea why this could be?

 

ModGUI gui = new ModGUI();
mc.displayGuiScreen(gui);

...

public ModGUI()
{
    super(new StringTextComponent("ModGUI"));
    	
    buttons.add(new Button(32, 32, 32, 100, "Click Me", (button) -> {
    	System.out.println("Clicked");
    }));
}

 

It can be any number of things based on how little you are showing. I do not know what your constructor is implying or what the gui is for (since you are specifically calling a client version with no server communication e.g. containers).  The one thing I do notice is that there is a method in Screen that adds a button for you. Please show your entire class and give context so we may accurately give a more meaningful response specific to your case.