Hi, thanks you for answer. The scroll area in my application is inside another widget, the main window, and it has an illustrated background. The problem is for main window not the content of the scroll area. Anyway, I found a workaround, I set the same background for the main window and the scroll bar, so the scroll bar is opaque but looks transparent. I still wonder why is there this strange behaviour with the scroll bar, but this topic can be considered as solved as I found a way to get around this.

Thanks but I asked same question on StackOverflow https://stackoverflow.com/questions/55471486/how-can-i-set-maximum-width-to-which-qscrollarea-within-qdialog-will-expand-wi/ The reason of such behaviour is cause QScrollArea::sizeHint() has boundedTo(QSize(36 * h, 24 * h)) , where h is fontMetrics().height(), at the end of implementation. So reimplementing sizeHint() is doing the job just fine

@AlexanderB Hi If you look here https://code.woboq.org/qt5/qtbase/src/widgets/styles/qwindowsstyle.cpp.html in 1894 void QWindowsStyle::drawComplexControl you can see the use of QRect groove = proxy()->subControlRect(CC_Slider, slider, SC_SliderGroove, widget); QRect handle = proxy()->subControlRect(CC_Slider, slider, SC_SliderHandle, widget); I assume you can get the various parts this way, even you changed it using stylesheet.

I was thinking about the widgets. By the way, how are you adding them to the QScrollArea ?

Thank You @SGaist and @AndyS. I am able to get QToolButton of QTabBar by applying Fusion style. I applied Fusion Style By: #include "mainwindow.h" #include <QTimer> #include <QtGlobal> #include <QFile> #include <QLocale> #include <QSplashScreen> #include <QGuiApplication> #include <qstylefactory.h> int main(int argc, char *argv[]) { QLocale::setDefault(QLocale::system()); QApplication a(argc, argv); a.setStyle(QStyleFactory::create("Fusion")); MainWindow w; w.showMaximized(); return a.exec(); }

@raven-worx my bad, Thanks for the link it helped a lot.

Hi You did read ? http://doc.qt.io/qt-5/stylesheet-examples.html#customizing-qscrollbar

Great ! Thanks for sharing your findings ! One last thing, you are leaking your opt object. You should rather build it on the stack and pass its address to subControlRect.

AFAIK, the Qt 4.8 series has no release officially supporting such a recent version of macOS. Therefore you may have surprises. Note that Qt 4 has reached end of life so unless you are locked to that version, you should really consider updating to Qt 5 which is now at it's 5.9.0 release.

@SGaist Thanks I managed to do it this way.

@the_ no it is Qt::ScrollBarAsNeeded.but scrolbar appears correctly after I resize the main widget even with 1 px.

hi I have never tried this myself so might be silly question, If you set the qtableview to always show horz scrollbar (Qt::ScrollBarPolicy) and then replace it with your own. the size should fit? Or is because your new scrollbar is bigger? (than the std one) the docs says "When a scroll bar becomes visible again, the viewport shrinks in order to make room for the scroll bar." so it should just work by auto. So I wonder if the custom bar dont give correct size info?

Hi and welcome I think you might need to set margin for inner area The following works for me with 32x32 images for the ends /*inner area*/ QScrollBar::vertical { border: 1px solid #a5a5a5; background: none; width: 65px; margin: 42px 0 42px 0; /* match top/lower area*/ } /*the knob*/ QScrollBar::handle:vertical { background: #d5d5d5;; border: 2px solid #000000; min-height: 60px; border-radius: 12px; } /*lower arrow area*/ QScrollBar::add-line:vertical { border: 0px solid grey; background: NONE; height: 40px; subcontrol-position: bottom; subcontrol-origin: margin; } /*top arrow area*/ QScrollBar::sub-line:vertical { border: 0px solid grey; background: none; height: 40px; subcontrol-position: top; subcontrol-origin: margin; } /*arrows*/ QScrollBar::up-arrow:vertical { image: url(:/GFX/sbar/up_arrow_scrollbar.png); } /*pressed*/ QScrollBar::up-arrow:vertical::pressed { image: url(:/GFX/sbar/up_arrow_scrollbar_pressed.png); } QScrollBar::down-arrow:vertical::pressed { image: url(:/GFX/sbar/down_arrow_scrollbar_pressed.png); } QScrollBar::down-arrow:vertical { /* border: 2px solid grey; width: 3px; height: 23px; */ image: url(:/GFX/sbar/down_arrow_scrollbar.png); } QScrollBar::add-page:vertical, QScrollBar::sub-page:vertical { background: none; }

ah. the _scrollAreaLayer does respect the size limits then. Good to know.

First of all I have never done what you wanted, so my advises might not work well You might want to override : void QAbstractScrollArea::setupViewport ( QWidget * viewport ) [protected slot] This slot is called by QAbstractScrollArea after setViewport(viewport) has been called. Reimplement this function in a subclass of QAbstractScrollArea to initialize the new viewport before it is used. You can actually either hide scrollbar provided by QAbstractScrollArea and display your own instead or subclass scrollbar and set it to itemView.

I did not meant to reimplement setRepeatAction, just use it in a subclass