Graphic problems with libgdx stage2d.ui

Question

I'm playing with stage2d.ui... Just creating an empty stage with only a button, and it happens this in android (screenshot directly from a Nexus5):

Also, it looks ok in desktop, but if you resize the screen, you can see the image of the button flickering at its previous position like this (image after making the window a bit more width):

I'm not sure if I'm doing something wrong or it's just a graphic issue...

For the button widget, I'm using the test data like this:

stage = new Stage(new ScreenViewport());
Skin skin = new Skin(Gdx.files.internal("uiskin.json"));

TextButton button = new TextButton("Button 1", skin);
button.setSize(100, 50);
button.setPosition(10, 10);

stage.addActor(button);

And then in the main render method, stage.act(delta) and stage.draw() are called, of course.

For the resize part... here's the code

public void resize(int width, int height) {
    stage.getViewport().update(width, height);
}

I have other stages without ui widgets working fine, but this is my first time with ui and I'm not sure about what's happening here...

Answer 1

Moved from comment above.

My guess is you are not clearing the screen at the start of your render method. Try adding Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); if it isn't there already.