ADDITIONAL SYSTEM INFORMATION :
Microsoft Windows [Version 10.0.17134.765]
openjdk version "11.0.3" 2019-04-16
OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.3+7)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.3+7, mixed mode)

A DESCRIPTION OF THE PROBLEM :
Window content is shrunk when run on 125% DPI. Due to size caching done in Region class, methods like prefHeight( -1 ) previously cached sizes, not snapped with actual output scale. This result in scroll pane's shrunk content issues.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Preconditions:
Two screens environment:
- left side monitor 125% DPI,
- right side monitor 100% DPI.
Application starts on left monitor by default.


Startup application from given source code and observe scrollbars visibility.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
scrollbars should not be visible because scroll pane has fitToWidth and fitToHeight properties and they are not visible on 100% DPI screen
ACTUAL -
scroll bars are visible, content is shrunk

---------- BEGIN SOURCE ----------
package com.example;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Orientation;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.Region;
import javafx.stage.Stage;

public class HiDpiIssue2Sample
{

    public static void main( String[] args )
    {
        System.err.println( Runtime.version().toString() );
        Application.launch( MainFx.class, args );
    }

    public static class MainFx extends Application
    {

        @Override
        public void start( final Stage primaryStage ) throws Exception
        {
            final BorderPane borderPane = new BorderPane();
            final BorderPane topContentPanel_layeredPane = new BorderPane();
            topContentPanel_layeredPane.setId( "TopContentPanel.layeredPane" );
            borderPane.setCenter( topContentPanel_layeredPane );

            //region bottom
            final BorderPane buttonBar = new BorderPane();
            borderPane.setBottom( buttonBar );
            final Button ok = new Button( "Fix issues" );
            ok.setOnAction( event -> {
                relayoutAll( primaryStage );
                primaryStage.sizeToScene();
            } );
            final FlowPane flowPane = new FlowPane( Orientation.HORIZONTAL, 10, 10, ok );
            flowPane.setAlignment( Pos.BASELINE_RIGHT );
            flowPane.setPadding( new Insets( 10 ) );
            buttonBar.setCenter( flowPane );

            final BorderPane topContentPanel_container = new BorderPane();
            topContentPanel_layeredPane.setCenter( topContentPanel_container );

            final var sp = new ScrollPane();
            sp.setFitToHeight( true );
            sp.setFitToWidth( true );
            sp.setPadding( Insets.EMPTY );
            topContentPanel_container.setCenter( sp );
            final BorderPane inputViewBp = new BorderPane();
            inputViewBp.setPadding( new Insets( 0, 0, 5, 0 ) );
            sp.setContent( inputViewBp );

            // This part is causing issues, because it is not relayouted on output scale change
            final BorderPane headerBp = new BorderPane();
            headerBp.setLeft( createLabel( 133, 50 ) );
            headerBp.setRight( createLabel( 351, 100 ) );
            inputViewBp.setTop( headerBp );

            final Scene aScene = new Scene( borderPane );
            primaryStage.setScene( aScene );
            primaryStage.sizeToScene();
            primaryStage.show();
        }

        private void relayoutAll( final Stage aPrimaryStage )
        {
            relayoutImpl( aPrimaryStage.getScene().getRoot() );
            aPrimaryStage.sizeToScene();
        }

        private void relayoutImpl( final Parent aRoot )
        {
            for( final Node node : aRoot.getChildrenUnmodifiable() )
            {
                if( node instanceof Parent )
                {
                    relayoutImpl( ( (Parent)node ) );
                }
                if( node instanceof Region )
                {
                    ( (Region)node ).requestLayout();
                }
            }
        }

        private static Label createLabel( final int width, final int height )
        {
            return new Label( width + "/" + height + "px width/height" )
            {

                @Override
                protected double computeMinWidth( final double height )
                {
                    return snapSizeX( width );
                }

                @Override
                protected double computeMinHeight( final double width )
                {
                    return snapSizeY( height );
                }

                @Override
                protected double computePrefHeight( final double width )
                {
                    return snapSizeY( height );
                }

                @Override
                protected double computePrefWidth( final double height )
                {
                    return snapSizeX( width );
                }
            };
        }

    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Please press "Fix issues" button

FREQUENCY : always