Fix a regression where dynamic tooltips wouldn't show up in Cocoa.

Tracking of mouse events was only enabled when enableMouseTracking or
Hover or a tooltip had been set explictly on the item, but this meant
that the dynamic QEvent::Tooltips would never get dispatched. So, in
order to help out people that might use this feature, all QCocoaViews
must pay the mouse move event tax *sigh*.

I added comments in the proper places so that we DO the right thing for
a release where we can force the change in behavior.

Task-number: 257320
Reviewed-by: Denis

2 files changed, 15 insertions, 4 deletions

diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index 40795d1787..c6af728884 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -3724,6 +3724,13 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
                     }
                 }
 
+                // ### Qt 5 These dynamic tool tips should be an OPT-IN feature. Some platforms
+                // like Mac OS X (probably others too), can optimize their views by not
+                // dispatching mouse move events. We have attributes to control hover,
+                // and mouse tracking, but as long as we are deciding to implement this
+                // feature without choice of opting-in or out, you ALWAYS have to have
+                // tracking enabled. Therefore, the other properties give a false sense of
+                // performance enhancement.
                 if (e->type() == QEvent::MouseMove && mouse->buttons() == 0) {
                     d->toolTipWidget = w;
                     d->toolTipPos = relpos;
diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index ae3265b91b..17e331301c 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -564,11 +564,15 @@ extern "C" {
             [self removeTrackingArea:t];
         }
     }
+
+    // Ideally, we shouldn't have NSTrackingMouseMoved events included below, it should
+    // only be turned on if mouseTracking, hover is on or a tool tip is set.
+    // Unfortunately, Qt will send "tooltip" events on mouse moves, so we need to
+    // turn it on in ALL case. That means EVERY QCocoaView gets to pay the cost of
+    // mouse moves delivered to it (Apple recommends keeping it OFF because there
+    // is a performance hit). So it goes.
     NSUInteger trackingOptions = NSTrackingMouseEnteredAndExited | NSTrackingActiveInActiveApp
-                                 | NSTrackingInVisibleRect;
-    if (qwidget->hasMouseTracking() || !qwidgetprivate->toolTip.isEmpty()
-        || qwidget->testAttribute(Qt::WA_Hover))
-        trackingOptions |= NSTrackingMouseMoved;
+                                 | NSTrackingInVisibleRect | NSTrackingMouseMoved;
     NSTrackingArea *ta = [[NSTrackingArea alloc] initWithRect:NSMakeRect(0, 0,
                                                                          qwidget->width(),
                                                                          qwidget->height())