Program: 30199
Project: 30199
Buggy source:
@Override public void create(){
  skin=new BladeSkin(Gdx.files.internal(SKIN));
  EditorLogger.setDebug();
  stage=new Stage(new ScreenViewport());
  Gdx.input.setInputProcessor(stage);
  setCtx();
  Message.init(skin);
  scnEditor=new ScnEditor(skin);
  scnEditor.setBackground("String_Node_Str");
  skin.getFont("String_Node_Str").getData().markupEnabled=true;
  ScenePanel scenePanel=new ScenePanel(skin);
  ActorPanel actorPanel=new ActorPanel(skin);
  Table rightPanel=new Table(skin);
  rightPanel.top().left();
  rightPanel.add(actorPanel).expand().fill().left();
  rightPanel.setBackground("String_Node_Str");
  SplitPane splitPaneRight=new SplitPane(scnEditor,rightPanel,false,skin);
  splitPaneRight.setSplitAmount(0.75f);
  ProjectPanel projectPanel=new ProjectPanel(skin);
  Image img=new Image(Ctx.assetManager.getIcon("String_Node_Str"));
  img.setScaling(Scaling.none);
  img.setAlign(Align.left);
  Table leftPanel=new Table(skin);
  leftPanel.top().left().padLeft(10);
  leftPanel.add(img).expand().fill().padBottom(20).padTop(20).padLeft(0).left();
  leftPanel.row();
  leftPanel.add(new ProjectToolbar(skin)).expandX().fill().left();
  leftPanel.row();
  leftPanel.add(projectPanel).expand().fill().left();
  leftPanel.row();
  leftPanel.add(scenePanel).expand().fill().left();
  leftPanel.setBackground("String_Node_Str");
  SplitPane splitPaneLeft=new SplitPane(leftPanel,splitPaneRight,false,skin);
  splitPaneLeft.setFillParent(true);
  splitPaneLeft.setSplitAmount(0.25f);
  stage.addActor(splitPaneLeft);
  String lastProject=Ctx.project.getEditorConfig().getProperty(Project.LAST_PROJECT_PROP,"String_Node_Str");
  if (!lastProject.isEmpty() && new File(lastProject).exists()) {
    try {
      EditorLogger.debug("String_Node_Str" + lastProject);
      Ctx.project.loadProject(new File(lastProject));
      if (!Ctx.project.checkVersion()) {
        new Dialog("String_Node_Str",skin){
          protected void result(          Object object){
            if (((Boolean)object).booleanValue()) {
              try {
                Ctx.project.updateEngineVersion();
                Message.showMsg(getStage(),"String_Node_Str",3);
              }
 catch (              IOException e1) {
                String msg="String_Node_Str" + e1.getClass().getSimpleName() + "String_Node_Str"+ e1.getMessage();
                Message.showMsgDialog(getStage(),"String_Node_Str",msg);
                EditorLogger.error(msg,e1);
              }
            }
          }
        }
.text("String_Node_Str" + Ctx.project.getProjectBladeEngineVersion() + "String_Node_Str").button("String_Node_Str",true).button("String_Node_Str",false).key(Keys.ENTER,true).key(Keys.ESCAPE,false).show(stage);
      }
    }
 catch (    Exception e) {
      EditorLogger.error("String_Node_Str",e);
      Ctx.project.closeProject();
    }
  }
  stage.setScrollFocus(scnEditor.getScnWidget());
  stage.setKeyboardFocus(scnEditor.getScnWidget());
  TooltipManager.getInstance().instant();
}

Fixed version (ground truth):
@Override public void create(){
  Gdx.graphics.setWindowedMode(Math.max((int)(Gdx.graphics.getDisplayMode().width * 0.9),1920 / 2),Math.max((int)(Gdx.graphics.getDisplayMode().height * 0.9),1080 / 2));
  skin=new BladeSkin(Gdx.files.internal(SKIN));
  EditorLogger.setDebug();
  stage=new Stage(new ScreenViewport());
  Gdx.input.setInputProcessor(stage);
  setCtx();
  Message.init(skin);
  scnEditor=new ScnEditor(skin);
  scnEditor.setBackground("String_Node_Str");
  skin.getFont("String_Node_Str").getData().markupEnabled=true;
  ScenePanel scenePanel=new ScenePanel(skin);
  ActorPanel actorPanel=new ActorPanel(skin);
  Table rightPanel=new Table(skin);
  rightPanel.top().left();
  rightPanel.add(actorPanel).expand().fill().left();
  rightPanel.setBackground("String_Node_Str");
  SplitPane splitPaneRight=new SplitPane(scnEditor,rightPanel,false,skin);
  splitPaneRight.setSplitAmount(0.75f);
  ProjectPanel projectPanel=new ProjectPanel(skin);
  Image img=new Image(Ctx.assetManager.getIcon("String_Node_Str"));
  img.setScaling(Scaling.none);
  img.setAlign(Align.left);
  Table leftPanel=new Table(skin);
  leftPanel.top().left().padLeft(10);
  leftPanel.add(img).expand().fill().padBottom(20).padTop(20).padLeft(0).left();
  leftPanel.row();
  leftPanel.add(new ProjectToolbar(skin)).expandX().fill().left();
  leftPanel.row();
  leftPanel.add(projectPanel).expand().fill().left();
  leftPanel.row();
  leftPanel.add(scenePanel).expand().fill().left();
  leftPanel.setBackground("String_Node_Str");
  SplitPane splitPaneLeft=new SplitPane(leftPanel,splitPaneRight,false,skin);
  splitPaneLeft.setFillParent(true);
  splitPaneLeft.setSplitAmount(0.25f);
  stage.addActor(splitPaneLeft);
  String lastProject=Ctx.project.getEditorConfig().getProperty(Project.LAST_PROJECT_PROP,"String_Node_Str");
  if (!lastProject.isEmpty() && new File(lastProject).exists()) {
    try {
      EditorLogger.debug("String_Node_Str" + lastProject);
      Ctx.project.loadProject(new File(lastProject));
      if (!Ctx.project.checkVersion()) {
        new Dialog("String_Node_Str",skin){
          protected void result(          Object object){
            if (((Boolean)object).booleanValue()) {
              try {
                Ctx.project.updateEngineVersion();
                Message.showMsg(getStage(),"String_Node_Str",3);
              }
 catch (              IOException e1) {
                String msg="String_Node_Str" + e1.getClass().getSimpleName() + "String_Node_Str"+ e1.getMessage();
                Message.showMsgDialog(getStage(),"String_Node_Str",msg);
                EditorLogger.error(msg,e1);
              }
            }
          }
        }
.text("String_Node_Str" + Ctx.project.getProjectBladeEngineVersion() + "String_Node_Str").button("String_Node_Str",true).button("String_Node_Str",false).key(Keys.ENTER,true).key(Keys.ESCAPE,false).show(stage);
      }
    }
 catch (    Exception e) {
      EditorLogger.error("String_Node_Str",e);
      Ctx.project.closeProject();
    }
  }
  stage.setScrollFocus(scnEditor.getScnWidget());
  stage.setKeyboardFocus(scnEditor.getScnWidget());
  TooltipManager.getInstance().instant();
}