LibGDX and Scene2d - simple menu issue

Newbie & Debugging Questions
#1

I am using LibGDX and Scene2D to create a simple menu for my game.

Here is a simple example that works for me:

    table.add(gameLogo).row();
    table.add(button1).row();
    table.add(button2).row();
    table.add(button3).row();

I didn’t include the irrelevant code(including the table into the stage for example).

If I don’t include .row() to each object that I add to the table, then the menu isn’t aligning to the center, which is very odd, for example:

    table.add(gameLogo).row();
    table.add(button1);
    table.add(button2).row();
    table.add(button3);

Why is the menu behaving like that? should I use more Tables or add some HorizontalGroups perhaps?

If you need any additional information, or images I can provide, although it does the same for even the simplest menu implemention possible with LibGDX and Scene2d.