1 files changed, 39 insertions, 27 deletions

diff --git a/src/plugins/platforms/cocoa/qnsview_mouse.mm b/src/plugins/platforms/cocoa/qnsview_mouse.mm
index 3d6471005d..49c94f18db 100644
--- a/src/plugins/platforms/cocoa/qnsview_mouse.mm
+++ b/src/plugins/platforms/cocoa/qnsview_mouse.mm
@@ -39,6 +39,22 @@
 
 // This file is included from qnsview.mm, and only used to organize the code
 
+/*
+    The reason for using this helper is to ensure that QNSView doesn't implement
+    the NSResponder callbacks for mouseEntered, mouseExited, and mouseMoved.
+
+    If it did, we would get mouse events though the responder chain as well,
+    for example if a subview has a tracking area of its own and calls super
+    in the handler, which results in forwarding the event though the responder
+    chain. The same applies if NSWindow.acceptsMouseMovedEvents is YES.
+
+    By having a helper as the target for our tracking areas, we know for sure
+    that the events we are getting stem from our own tracking areas.
+
+    FIXME: Ideally we wouldn't need this workaround, and would correctly
+    interact with the responder chain by e.g. calling super if Qt does not
+    accept the mouse event
+*/
 @implementation QT_MANGLE_NAMESPACE(QNSViewMouseMoveHelper) {
     QNSView *view;
 }
@@ -135,6 +151,28 @@
 
 @implementation QT_MANGLE_NAMESPACE(QNSView) (Mouse)
 
+- (void)initMouse
+{
+    NSUInteger trackingOptions = NSTrackingActiveInActiveApp
+        | NSTrackingMouseEnteredAndExited | NSTrackingCursorUpdate;
+
+    // Ideally, NSTrackingMouseMoved should be turned on only if QWidget::mouseTracking
+    // is enabled, 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 QWindow
+    // gets to pay the cost of mouse moves delivered to it (Apple recommends keeping it OFF
+    // because there is a performance hit).
+    trackingOptions |= NSTrackingMouseMoved;
+
+    // Using NSTrackingInVisibleRect means AppKit will automatically synchronize the
+    // tracking rect with changes in the view's visible area, so leave it undefined.
+    trackingOptions |= NSTrackingInVisibleRect;
+    static const NSRect trackingRect = NSZeroRect;
+
+    QMacAutoReleasePool pool;
+    [self addTrackingArea:[[[NSTrackingArea alloc] initWithRect:trackingRect
+        options:trackingOptions owner:m_mouseMoveHelper userInfo:nil] autorelease]];
+}
+
 - (BOOL)acceptsFirstMouse:(NSEvent *)theEvent
 {
     Q_UNUSED(theEvent)
@@ -406,35 +444,9 @@
         [super otherMouseUp:theEvent];
 }
 
-- (void)updateTrackingAreas
-{
-    [super updateTrackingAreas];
-
-    QMacAutoReleasePool pool;
-
-    // NSTrackingInVisibleRect keeps care of updating once the tracking is set up, so bail out early
-    if (m_trackingArea && [[self trackingAreas] containsObject:m_trackingArea])
-        return;
-
-    // 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 QWindow 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 | NSTrackingMouseMoved | NSTrackingCursorUpdate;
-    [m_trackingArea release];
-    m_trackingArea = [[NSTrackingArea alloc] initWithRect:[self frame]
-                                                  options:trackingOptions
-                                                    owner:m_mouseMoveHelper
-                                                 userInfo:nil];
-    [self addTrackingArea:m_trackingArea];
-}
-
 - (void)cursorUpdate:(NSEvent *)theEvent
 {
-    qCDebug(lcQpaMouse) << "[QNSView cursorUpdate:]" << self.cursor;
+    qCDebug(lcQpaMouse) << "Updating cursor for" << self << "to" << self.cursor;
 
     // Note: We do not get this callback when moving from a subview that
     // uses the legacy cursorRect API, so the cursor is reset to the arrow