widgets/wrapper: update child geometry when implicit size changes

The implicit size update from a child item of a MarginWrapper
component triggers an implicit size update of the wrapper component,
but this does not necessarily result in the actual size of the wrapper
changing (e.g. when it is positioned by a layout).

src/widgets/marginwrapper.cpp

@@ -27,14 +27,14 @@ void MarginWrapperManager::componentComplete() {
 		    this->mWrapper,
 		    &QQuickItem::widthChanged,
 		    this,
-		    &MarginWrapperManager::onWrapperWidthChanged
+		    &MarginWrapperManager::updateChildX
 		);
 
 		QObject::connect(
 		    this->mWrapper,
 		    &QQuickItem::heightChanged,
 		    this,
-		    &MarginWrapperManager::onWrapperHeightChanged
+		    &MarginWrapperManager::updateChildY
 		);
 	}
 
@@ -112,13 +112,13 @@ qreal MarginWrapperManager::targetChildY() const {
 	}
 }
 
-void MarginWrapperManager::onWrapperWidthChanged() {
+void MarginWrapperManager::updateChildX() {
 	if (!this->mChild || !this->mWrapper) return;
 	this->mChild->setX(this->targetChildX());
 	this->mChild->setWidth(this->targetChildWidth());
 }
 
-void MarginWrapperManager::onWrapperHeightChanged() {
+void MarginWrapperManager::updateChildY() {
 	if (!this->mChild || !this->mWrapper) return;
 	this->mChild->setY(this->targetChildY());
 	this->mChild->setHeight(this->targetChildHeight());
@@ -127,11 +127,19 @@ void MarginWrapperManager::onWrapperHeightChanged() {
 void MarginWrapperManager::onChildImplicitWidthChanged() {
 	if (!this->mChild || !this->mWrapper) return;
 	this->mWrapper->setImplicitWidth(this->mChild->implicitWidth() + this->mMargin * 2);
+
+	// If the implicit width change does not result in an actual width change,
+	// this will not be called anywhere else.
+	this->updateChildX();
 }
 
 void MarginWrapperManager::onChildImplicitHeightChanged() {
 	if (!this->mChild || !this->mWrapper) return;
 	this->mWrapper->setImplicitHeight(this->mChild->implicitHeight() + this->mMargin * 2);
+
+	// If the implicit height change does not result in an actual height change,
+	// this will not be called anywhere else.
+	this->updateChildY();
 }
 
 void MarginWrapperManager::updateGeometry() {

src/widgets/marginwrapper.hpp

@@ -55,8 +55,8 @@ signals:
 
 private slots:
 	void onChildChanged();
-	void onWrapperWidthChanged();
-	void onWrapperHeightChanged();
+	void updateChildX();
+	void updateChildY();
 	void onChildImplicitWidthChanged();
 	void onChildImplicitHeightChanged();