Fix video seeking.

Regression was introduced in d0e854e9d8.

Each time you hide() a widget its mousePress state is reset and
mouseMoveEvent() / mouseReleaseEvent() handlers are never called.

So you can't toggle (hide + show) widgets that are mouse-pressed.

Fixes #4802.

Telegram/SourceFiles/media/view/media_clip_controller.cpp

@@ -79,17 +79,21 @@ template <typename Callback>
 void Controller::startFading(Callback start) {
 	if (!_fadeAnimation->animating()) {
 		showChildren();
-		_playbackSlider->hide();
+		_playbackSlider->disablePaint(true);
 		_childrenHidden = false;
 	}
 	start();
 	if (_fadeAnimation->animating()) {
-		hideChildren();
+		for (const auto child : children()) {
+			if (child->isWidgetType() && child != _playbackSlider) {
+				static_cast<QWidget*>(child)->hide();
+			}
+		}
 		_childrenHidden = true;
 	} else {
 		fadeFinished();
 	}
-	_playbackSlider->show();
+	_playbackSlider->disablePaint(false);
 }
 
 void Controller::showAnimated() {

Telegram/SourceFiles/mediaview.cpp

@@ -2961,9 +2961,6 @@ bool MediaView::eventFilter(QObject *obj, QEvent *e) {
 				activate = true;
 			}
 			if (activate) {
-				if (_controlsState == ControlsHiding || _controlsState == ControlsHidden) {
-					int a = 0;
-				}
 				activateControls();
 			}
 		}

Telegram/SourceFiles/ui/widgets/continuous_sliders.cpp

@@ -195,7 +195,14 @@ float64 MediaSlider::getOverDuration() const {
 	return _st.duration;
 }
 
+void MediaSlider::disablePaint(bool disabled) {
+	_paintDisabled = disabled;
+}
+
 void MediaSlider::paintEvent(QPaintEvent *e) {
+	if (_paintDisabled) {
+		return;
+	}
 	Painter p(this);
 	PainterHighQualityEnabler hq(p);
 

Telegram/SourceFiles/ui/widgets/continuous_sliders.h

@@ -124,6 +124,7 @@ public:
 		_alwaysDisplayMarker = alwaysDisplayMarker;
 		update();
 	}
+	void disablePaint(bool disabled);
 
 protected:
 	void paintEvent(QPaintEvent *e) override;
@@ -134,6 +135,7 @@ private:
 
 	const style::MediaSlider &_st;
 	bool _alwaysDisplayMarker = false;
+	bool _paintDisabled = false;
 
 };