QSplitter becoming undistinguishable between QWidget and QTabWidget

Question

I am puting a QWidget and a QTabWidget next to each other in one horisontal splitter. And the splitter loses it\'s shape, you can know that there is a splitter only by hovering

Answer 1

Call splitter_handles {} with the QSplitter you want to add handles to:

#include "splitter_handles.h"
...
QSplitter spl {};
... // widgets added to 'spl'
plitter_handles {spl}; // adding handles
...

Result:

splitter_handles.h

#ifndef SPLITTER_HANDLES_H
#define SPLITTER_HANDLES_H

#include 
#include 
#include 

class handle : public QWidget
{
    Q_OBJECT

protected:
    void paintEvent(QPaintEvent *e) {
        Q_UNUSED(e);
        QPainter painter {this};
        painter.setPen(Qt::NoPen);
        painter.setBrush(Qt::Dense4Pattern);
        painter.drawRect(this->rect());
    }
};

class splitter_handles {
public:
    splitter_handles(QSplitter * spl) {
        const int width {7};
        spl->setHandleWidth(width);
        for(int h_idx {1}; h_idx < spl->count(); h_idx++) {
            auto l_handle {new handle {}};
            l_handle->setMaximumSize(width*2, width*2);

            auto layout {new QHBoxLayout {spl->handle(h_idx)}};
            layout->setSpacing(0);
            layout->setMargin(1);
            layout->addWidget(l_handle);
        }
    }
};

#endif // SPLITTER_HANDLES_H

main.c

#include 
#include 
#include 
#include 

#include "splitter_handles.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    auto spl_v {new QSplitter {Qt::Vertical}};
    spl_v->addWidget(new QGroupBox {"box 1"});
    spl_v->addWidget(new QGroupBox {"box 2"});
    spl_v->addWidget(new QGroupBox {"box 3"});
    splitter_handles {spl_v}; // set handles

    auto wdg  {new QWidget {}};
    auto v_lt {new QVBoxLayout {wdg}};
    v_lt->addWidget(spl_v);
    v_lt->setMargin(0);

    auto spl_h {new QSplitter {}};
    spl_h->addWidget(wdg);
    spl_h->addWidget(new QGroupBox {"box 4"});
    spl_h->addWidget(new QGroupBox {"box 5"});
    splitter_handles {spl_h};

    auto h_lt {new QHBoxLayout {}};
    h_lt->addWidget(spl_h);

    QWidget w {};
    w.setLayout(h_lt);
    w.setGeometry(100,100,500,300);
    w.show();

    return a.exec();
}