Unwanted padding when using QWidgets and QGroupBox in QT

Question

I'm having a huge problem with unwanted padding on one of my Widgets. This is how its set up:

First I have a MainWindow which has a QGridLayout with margin, padding and contentsMargins all set to 0. In that I put a QGroupBox on position 0,0 and on 0,1 I put a QWidget I made. The QWidget is made continas a QGridLayout (with the same margins etc, all set to 0) and in that layout I place a QGroupBox on 0,0(which contains a layout where i put all the buttons) and another View on the 1,0. The MainMenu QGroupBox and the "test" should in theory be aligned since I removed all padding and margins to 0. The reason why the right hand side is a widget is so that I easily can replace it with something else.

The weirdest this is that on the bottom of the windows, the MainMenu GroupBox and the right hand sides widget are aligned. Is just at the top they dont meet up. Would be really thankful if anyone could solve my problem. My last resort is to but the MainMenu into its own Widget. It feels like the box feels like its a child and the MainMenu is higher up on the hierarchy. But that doesnt explain why they are aligned on the bottom.

Answer 1

It certainly looks like the layout containing the "test" group box has a top margin set, so I would definitely check that again carefully. And then check it again :)

Could you possibly have set the font for the "test" group box to some font type or size that may be throwing things off?

Are you applying a style sheet that may be affecting things?

Edit:

I've included the .ui and resulting code in .h from my experiment with the layouts you describe as requested in comments.

mainwindow.ui:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>376</width>
    <height>433</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralWidget">
   <layout class="QGridLayout" name="gridLayout" columnstretch="0,0">
    <property name="margin">
     <number>0</number>
    </property>
    <property name="spacing">
     <number>0</number>
    </property>
    <item row="0" column="0">
     <widget class="QGroupBox" name="groupBox">
      <property name="title">
       <string>GroupBox</string>
      </property>
      <property name="flat">
       <bool>false</bool>
      </property>
     </widget>
    </item>
    <item row="0" column="1">
     <widget class="QWidget" name="widget" native="true">
      <layout class="QGridLayout" name="gridLayout_2">
       <property name="margin">
        <number>0</number>
       </property>
       <property name="spacing">
        <number>0</number>
       </property>
       <item row="0" column="0">
        <widget class="QGroupBox" name="groupBox_2">
         <property name="title">
          <string>GroupBox</string>
         </property>
         <property name="alignment">
          <set>Qt::AlignLeading|Qt::AlignLeft|Qt::AlignVCenter</set>
         </property>
         <property name="flat">
          <bool>false</bool>
         </property>
        </widget>
       </item>
       <item row="1" column="0">
        <widget class="QWidget" name="widget_2" native="true"/>
       </item>
      </layout>
     </widget>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>376</width>
     <height>21</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>

..interesting part of ui_mainwindow.h

public:
    QWidget *centralWidget;
    QGridLayout *gridLayout;
    QGroupBox *groupBox;
    QWidget *widget;
    QGridLayout *gridLayout_2;
    QGroupBox *groupBox_2;
    QWidget *widget_2;
    QMenuBar *menuBar;
    QToolBar *mainToolBar;
    QStatusBar *statusBar;

    void setupUi(QMainWindow *MainWindow)
    {
        if (MainWindow->objectName().isEmpty())
            MainWindow->setObjectName(QString::fromUtf8("MainWindow"));
        MainWindow->resize(376, 433);
        centralWidget = new QWidget(MainWindow);
        centralWidget->setObjectName(QString::fromUtf8("centralWidget"));
        gridLayout = new QGridLayout(centralWidget);
        gridLayout->setSpacing(0);
        gridLayout->setContentsMargins(0, 0, 0, 0);
        gridLayout->setObjectName(QString::fromUtf8("gridLayout"));
        groupBox = new QGroupBox(centralWidget);
        groupBox->setObjectName(QString::fromUtf8("groupBox"));
        groupBox->setFlat(false);

        gridLayout->addWidget(groupBox, 0, 0, 1, 1);

        widget = new QWidget(centralWidget);
        widget->setObjectName(QString::fromUtf8("widget"));
        gridLayout_2 = new QGridLayout(widget);
        gridLayout_2->setSpacing(0);
        gridLayout_2->setContentsMargins(0, 0, 0, 0);
        gridLayout_2->setObjectName(QString::fromUtf8("gridLayout_2"));
        groupBox_2 = new QGroupBox(widget);
        groupBox_2->setObjectName(QString::fromUtf8("groupBox_2"));
        QFont font;
        font.setFamily(QString::fromUtf8("MS Shell Dlg 2"));
        font.setPointSize(8);
        font.setBold(false);
        font.setWeight(50);
        font.setKerning(true);
        groupBox_2->setFont(font);
        groupBox_2->setAlignment(Qt::AlignLeading|Qt::AlignLeft|Qt::AlignVCenter);
        groupBox_2->setFlat(false);

        gridLayout_2->addWidget(groupBox_2, 0, 0, 1, 1);

        widget_2 = new QWidget(widget);
        widget_2->setObjectName(QString::fromUtf8("widget_2"));

        gridLayout_2->addWidget(widget_2, 1, 0, 1, 1);


        gridLayout->addWidget(widget, 0, 1, 1, 1);

        MainWindow->setCentralWidget(centralWidget);
        menuBar = new QMenuBar(MainWindow);
        menuBar->setObjectName(QString::fromUtf8("menuBar"));
        menuBar->setGeometry(QRect(0, 0, 376, 21));
        MainWindow->setMenuBar(menuBar);
        mainToolBar = new QToolBar(MainWindow);
        mainToolBar->setObjectName(QString::fromUtf8("mainToolBar"));
        MainWindow->addToolBar(Qt::TopToolBarArea, mainToolBar);
        statusBar = new QStatusBar(MainWindow);
        statusBar->setObjectName(QString::fromUtf8("statusBar"));
        MainWindow->setStatusBar(statusBar);

        retranslateUi(MainWindow);

        QMetaObject::connectSlotsByName(MainWindow);
    } // setupUi