Avoid keyboard focus for UI elements in the collapsed content area

Hide the content area when it is fully collapsed and make it visible
before starting the expand animation. This ensures that the children
of the content area do not receive the keyboard input focus when the
content area is collapsed.

GnuPG-bug-id: 6046

src/dialogs/certifywidget.cpp

@@ -92,6 +92,7 @@ AnimatedExpander::AnimatedExpander(const QString &title, QWidget *parent):
     // start out collapsed
     contentArea.setMaximumHeight(0);
     contentArea.setMinimumHeight(0);
+    contentArea.setVisible(false);
 
     // let the entire widget grow and shrink with its content
     toggleAnimation.addAnimation(new QPropertyAnimation(this, "minimumHeight"));
@@ -106,10 +107,20 @@ AnimatedExpander::AnimatedExpander(const QString &title, QWidget *parent):
     mainLayout.addWidget(&contentArea, row, 0, 1, 3);
     setLayout(&mainLayout);
     QObject::connect(&toggleButton, &QToolButton::clicked, [this](const bool checked) {
+        if (checked) {
+            // make the content visible when expanding starts
+            contentArea.setVisible(true);
+        }
         toggleButton.setArrowType(checked ? Qt::ArrowType::DownArrow : Qt::ArrowType::RightArrow);
         toggleAnimation.setDirection(checked ? QAbstractAnimation::Forward : QAbstractAnimation::Backward);
         toggleAnimation.start();
     });
+    connect(&toggleAnimation, &QAbstractAnimation::finished, [this]() {
+        // hide the content area when it is fully collapsed
+        if (!toggleButton.isChecked()) {
+            contentArea.setVisible(false);
+        }
+    });
 }
 
 void AnimatedExpander::setContentLayout(QLayout *contentLayout)