From dd2a871eaefe8925c88a835bf298180044d4b0e9 Mon Sep 17 00:00:00 2001
From: Sergio Martins <sergio.martins@kdab.com>
Date: Tue, 10 Jan 2017 17:03:17 +0000
Subject: [PATCH] Clear dock indicator when not over a floating dock group
 window

The rubberband is shown depending if there's a current hovered dock widget,
but there were a few places that were not calling updateGapIndicator().

Additionally, the rubberband will also disappear if the currentHoveredFloat
is destroyed externally (would leave a ghost rubber band behind).

Task-number: QTBUG-58049
Change-Id: Iafdf234aa04b0ee280e51f8fa2fd212c86610cd1
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
---
 src/widgets/widgets/qmainwindowlayout.cpp | 29 +++++++++++++++++++----
 src/widgets/widgets/qmainwindowlayout_p.h |  3 ++-
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/src/widgets/widgets/qmainwindowlayout.cpp b/src/widgets/widgets/qmainwindowlayout.cpp
index 72e06e4efa..68ca571acf 100644
--- a/src/widgets/widgets/qmainwindowlayout.cpp
+++ b/src/widgets/widgets/qmainwindowlayout.cpp
@@ -1951,6 +1951,27 @@ void QMainWindowLayout::invalidate()
     minSize = szHint = QSize();
 }
 
+#ifndef QT_NO_DOCKWIDGET
+void QMainWindowLayout::setCurrentHoveredFloat(QWidget *w)
+{
+    if (currentHoveredFloat != w) {
+        if (currentHoveredFloat) {
+            disconnect(currentHoveredFloat.data(), &QObject::destroyed,
+                       this, &QMainWindowLayout::updateGapIndicator);
+        }
+
+        currentHoveredFloat = w;
+
+        if (w) {
+            connect(w, &QObject::destroyed,
+                    this, &QMainWindowLayout::updateGapIndicator, Qt::UniqueConnection);
+        }
+
+        updateGapIndicator();
+    }
+}
+#endif //QT_NO_DOCKWIDGET
+
 /******************************************************************************
 ** QMainWindowLayout - remaining stuff
 */
@@ -2037,7 +2058,7 @@ bool QMainWindowLayout::plug(QLayoutItem *widgetItem)
             dropTo->setParent(floatingTabs);
             dropTo->show();
             dropTo->d_func()->plug(QRect());
-            currentHoveredFloat = floatingTabs;
+            setCurrentHoveredFloat(floatingTabs);
         }
 #endif // QT_CONFIG(tabwidget)
 #if QT_CONFIG(tabbar)
@@ -2190,7 +2211,7 @@ void QMainWindowLayout::animationFinished(QWidget *widget)
         currentGapPos.clear();
         pluggingWidget = 0;
 #if QT_CONFIG(dockwidget)
-        currentHoveredFloat = nullptr;
+        setCurrentHoveredFloat(nullptr);
 #endif
         //applying the state will make sure that the currentGap is updated correctly
         //and all the geometries (especially the one from the central widget) is correct
@@ -2497,12 +2518,12 @@ void QMainWindowLayout::hover(QLayoutItem *widgetItem, const QPoint &mousePos)
             if (!w->geometry().contains(mousePos))
                 continue;
 
-            currentHoveredFloat = w;
+            setCurrentHoveredFloat(w);
             restore(true);
             return;
         }
     }
-    currentHoveredFloat = Q_NULLPTR;
+    setCurrentHoveredFloat(nullptr);
 #endif //QT_NO_DOCKWIDGET
 
     QPoint pos = parentWidget()->mapFromGlobal(mousePos);
diff --git a/src/widgets/widgets/qmainwindowlayout_p.h b/src/widgets/widgets/qmainwindowlayout_p.h
index 857a05eb8e..ed8da61bc3 100644
--- a/src/widgets/widgets/qmainwindowlayout_p.h
+++ b/src/widgets/widgets/qmainwindowlayout_p.h
@@ -306,13 +306,13 @@ public:
 #endif
 #ifndef QT_NO_DOCKWIDGET
     QPointer<QWidget> currentHoveredFloat; // set when dragging over a floating dock widget
+    void setCurrentHoveredFloat(QWidget *w);
 #endif
 
     void hover(QLayoutItem *widgetItem, const QPoint &mousePos);
     bool plug(QLayoutItem *widgetItem);
     QLayoutItem *unplug(QWidget *widget, bool group = false);
     void revert(QLayoutItem *widgetItem);
-    void updateGapIndicator();
     void paintDropIndicator(QPainter *p, QWidget *widget, const QRegion &clip);
     void applyState(QMainWindowLayoutState &newState, bool animate = true);
     void restore(bool keepSavedState = false);
@@ -320,6 +320,7 @@ public:
     void animationFinished(QWidget *widget);
 
 private Q_SLOTS:
+    void updateGapIndicator();
 #ifndef QT_NO_DOCKWIDGET
 #ifndef QT_NO_TABBAR
     void tabChanged();