Qt crashes when having a dropshadow and opacity effect set to widgets

[TheGrudge]

Hi,

I have a container widget with an opacity effect assigned to it, and a child widget that contains QToolButtons. This child has a dropshadow effect applied to it.

The opacity effect is used for fading the widget in / out. It works fine without the dropshadow effect, but with it, it crashes as soon as I hover over a toolbutton.

This is my widget code:

class MapWidget(QgsMapCanvas):

    def __init__(self, parent=None):
        super().__init__(parent)

        self.legend = LegendWidget(self)
        self._showLegend = True

        self.controls = MapControlsWidget()
        self.controlsContainer = QWidget(self)
        layout = QVBoxLayout()
        layout.setContentsMargins(0, 0, 0, 0)
        layout.addWidget(self.controls)
        self.controlsContainer.setLayout(layout)

        self.controlsEffect = QGraphicsOpacityEffect(self)
        self.controlsEffect.setOpacity(0)
        self.controlsContainer.setGraphicsEffect(self.controlsEffect)
        self.controlsOpacityAnimation: QPropertyAnimation = None

        self.dropShadow = QGraphicsDropShadowEffect(self)
        self.dropShadow.setOffset(1)
        self.dropShadow.setBlurRadius(4)
        self.controls.setGraphicsEffect(self.dropShadow)

        self.controls.targetButton.clicked.connect(self.onTargetButtonClicked)
        self.controls.zoomInButton.clicked.connect(self.onZoomInButtonClicked)
        self.controls.zoomOutButton.clicked.connect(self.onZoomOutButtonClicked)

    def onTargetButtonClicked(self) -> None:
        if self.layers():
            self.zoomToSelected(self.layers()[0])

    def onZoomInButtonClicked(self) -> None:
        self.zoomIn()

    def onZoomOutButtonClicked(self) -> None:
        self.zoomOut()

    @pyqtProperty(bool)
    def showLegend(self) -> bool:
        return self._showLegend

    @showLegend.setter
    def showLegend(self, value: bool) -> None:
        self._showLegend = value
        self.legend.setVisible(value)

    def resizeEvent(self, e):
        super().resizeEvent(e)
        self.controlsContainer.setGeometry(
            QRect(self.width() - self.controls.width() - 10, 10, self.controls.width(), self.controls.height())
        )

    def enterEvent(self, *args, **kwargs):
        super().enterEvent(*args, **kwargs)

        self.controlsOpacityAnimation = QPropertyAnimation(self.controlsEffect, b"opacity")
        self.controlsOpacityAnimation.setDuration(350)
        self.controlsOpacityAnimation.setStartValue(0)
        self.controlsOpacityAnimation.setEndValue(1)
        self.controlsOpacityAnimation.setEasingCurve(QEasingCurve.OutBack)
        self.controlsOpacityAnimation.start(QPropertyAnimation.DeleteWhenStopped)

    def leaveEvent(self, *args, **kwargs):
        super().leaveEvent(*args, **kwargs)

        self.controlsOpacityAnimation = QPropertyAnimation(self.controlsEffect, b"opacity")
        self.controlsOpacityAnimation.setDuration(350)
        self.controlsOpacityAnimation.setStartValue(1)
        self.controlsOpacityAnimation.setEndValue(0)
        self.controlsOpacityAnimation.setEasingCurve(QEasingCurve.InBack)
        self.controlsOpacityAnimation.start(QPropertyAnimation.DeleteWhenStopped)

Am I doing something wrong? I don't understand why it is crashing when hovering over a button.