scene2d - Flicker of ImageTextButton in libgdx -

i'm creating store stage in libgdx using scene2d.ui package. i'm seeing weird flicker when showing stage larger versions of buttons appear behind smaller buttons:

the larger background buttons flicker on , off, while front ones appear normal. background ones aren't clickable, front ones - again, appear normal.

here relevant code:

private void init(skin skin) {    this.skin = skin;     boytexture = new texture(gdx.files.internal("images/character.png"));    cattexture = new texture(gdx.files.internal("images/character_cat_girl.png"));    horntexture = new texture(gdx.files.internal("images/character_horn_girl.png"));    pinktexture = new texture(gdx.files.internal("images/character_pink_girl.png"));    queentexture = new texture(gdx.files.internal("images/character_queen_girl.png"));     // set root table    table = new table();    table.setfillparent(true);    addactor(table);     table.add(new label("characters: ", skin, "default")).padleft(10).colspan(2);    table.row();    buttongroup charactergroup = new buttongroup();    charactergroup.setmaxcheckcount(1);    button boybutton = createimagetextbutton("plain boy", boytexture);    table.add(boybutton);    button catbutton = createimagetextbutton("cat girl", cattexture);    table.add(catbutton);    table.row();    button hornbutton = createimagetextbutton("horn girl", horntexture);    table.add(hornbutton);    button pinkbutton = createimagetextbutton("pink girl", pinktexture);    table.add(pinkbutton);    table.row();    button queenbutton = createimagetextbutton("queen", queentexture);    table.add(queenbutton).colspan(2);     //addaction(actions.sequence(actions.alpha(1f), actions.fadein(1))); }  private button createimagetextbutton(string label, texture texture) {    imagetextbutton button = new imagetextbutton(label, skin, "default");    button.getimage().setdrawable(new spritedrawable(new sprite(texture)));    return button; } 

at first thought had transition actions, can see i've commented them out , it's still happening.

i thought problem imagetextbutton, changed createimagetextbutton method return plain textbutton. still has flicker buttons aren't enlarged in background - seem flicker on sides same size foreground ones.

here constructors, requested in comments below:

public store(skin skin) {     super();     init(skin); }  public store(viewport viewport, skin skin) {     super(viewport);     init(skin); }  public store(viewport viewport, batch batch, skin skin) {     super(viewport, batch);     init(skin); } 

i'm using last 1 when creating stage in maingame class.

public class maingame extends applicationadapter {      public static final int min_width = 480;     public static final int min_height = 800;      public static spritebatch batch;     public static gamestage game;     public static store store;     public static skin skin;     public static viewport viewport;     public static stage stage;      @override     public void create() {         viewport = new extendviewport(min_width, min_height);         batch = new spritebatch();         initskin();         game = new gamestage(viewport, batch, skin);         store = new store(viewport, batch, skin);         setstage(game);     }      ...      @override     public void render() {         stage.act(gdx.graphics.getdeltatime());         stage.draw();     }      @override     public void resize(int width, int height) {         viewport.update(width, height, true);     }      ...      public static void setstage(stage stage) {         maingame.stage = stage;         gdx.input.setinputprocessor(stage);     } }