QT ImageViewer Tutorial crashes with QT Designer

[nipunamr]

My development environment is Visual studio 2015 with QT 5.6.3. I am creating forms using QT designer. I am doing several QT tutorials; specifically I am doing the following tutorial.

http://www.bogotobogo.com/Qt/Qt5_QMa...geViewer_B.php

The program essentially, displays an image using QScrollArea and QLabel. The program works if I create my "widgets" in visual studio (without QT designer)

//Here's the relevant code

imageLabel = new QLabel;
	imageLabel->setBackgroundRole(QPalette::Base);
	imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
	imageLabel->setScaledContents(true);
 
	scrollArea = new QScrollArea;
	scrollArea->setBackgroundRole(QPalette::Dark);
	scrollArea->setWidget(imageLabel);
	setCentralWidget(scrollArea);

imageLabel = new QLabel;
	imageLabel->setBackgroundRole(QPalette::Base);
	imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
	imageLabel->setScaledContents(true);

	scrollArea = new QScrollArea;
	scrollArea->setBackgroundRole(QPalette::Dark);
	scrollArea->setWidget(imageLabel);
	setCentralWidget(scrollArea);

To copy to clipboard, switch view to plain text mode 

As expected the scrollbars appear.

Then I created the widgets in QT Designer and tried to use it in visual studio. The one thing I noticed is that when I create a scrollArea using QT designer it also creates a QWidget called "ScrollAreaWidgetContents". See the attached "QT_Designer_1" and "QT_Inspector_Window" images. The problem is that I can't see scroll bars with this program. See the attached "Image_Viewer_No_ScrollBars". Here's the releavant code.

ui->label->setBackgroundRole(QPalette::Base);
	ui->label->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
	ui->label->setScaledContents(true);
 
	ui->scrollArea->setBackgroundRole(QPalette::Dark);
	ui->scrollArea->setWidget(ui->scrollAreaWidgetContents);
	ui->scrollArea->setWidgetResizable(true);
	ui->scrollAreaWidgetContents->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
	//ui->scrollArea->setWidget(ui->label);
	setCentralWidget(ui->scrollArea);

ui->label->setBackgroundRole(QPalette::Base);
	ui->label->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
	ui->label->setScaledContents(true);

	ui->scrollArea->setBackgroundRole(QPalette::Dark);
	ui->scrollArea->setWidget(ui->scrollAreaWidgetContents);
	ui->scrollArea->setWidgetResizable(true);
	ui->scrollAreaWidgetContents->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);
	//ui->scrollArea->setWidget(ui->label);
	setCentralWidget(ui->scrollArea);

To copy to clipboard, switch view to plain text mode 

I then tried to uncomment "ui->scrollArea->setWidget(ui->label)" line and the program crashes. See the attached "Image_Viewer_Crashes" I guess I don't understand why it's crashing. Could anyone help resolve this problem?

Thanks