fix quickly moving out of overlay not removing it

Author: DivineDominion

FatSidebar/FatSidebarItem.swift

@@ -475,6 +475,16 @@ public class FatSidebarItem: NSView {
             }
             overlay.overlayFinished = { [weak self] in self?.overlay = nil }
 
+            NotificationCenter.default.addObserver(
+                overlay,
+                selector: #selector(FatSidebarItemOverlay.hoverDidStart),
+                name: FatSidebarItemOverlay.hoverStarted,
+                object: nil)
+
+            if let scrollView = enclosingScrollView {
+                overlay.setupScrollSyncing(scrollView: scrollView)
+            }
+
             windowContentView.addSubview(overlay)
             (animated
                 ? overlay.animator()
@@ -488,16 +498,6 @@ public class FatSidebarItem: NSView {
                     return frame
             }()
 
-            NotificationCenter.default.addObserver(
-                overlay,
-                selector: #selector(FatSidebarItemOverlay.hoverDidStart),
-                name: FatSidebarItemOverlay.hoverStarted,
-                object: nil)
-
-            if let scrollView = enclosingScrollView {
-                overlay.setupScrollSyncing(scrollView: scrollView)
-            }
-
             return overlay
         }()
     }

FatSidebar/FatSidebarItemOverlay.swift

@@ -15,14 +15,23 @@ class FatSidebarItemOverlay: FatSidebarItem {
     // MARK: - Hovering 
 
     static var hoverStarted: Notification.Name { return Notification.Name(rawValue: "fat sidebar hover did start") }
+    var didExit = false
     var overlayFinished: (() -> Void)?
 
     private var trackingArea: NSTrackingArea?
 
     override func updateTrackingAreas() {
         super.updateTrackingAreas()
 
-        if let oldTrackingArea = trackingArea { self.removeTrackingArea(oldTrackingArea) }
+        if let oldTrackingArea = self.trackingArea { self.removeTrackingArea(oldTrackingArea) }
+
+        guard !didExit else { return }
+
+        createAndAssignTrackingArea()
+        fireEnteredOrExitedWithInitialMouseCoordinates()
+    }
+
+    fileprivate func createAndAssignTrackingArea() {
 
         let newTrackingArea = NSTrackingArea(
             rect: self.bounds,
@@ -33,7 +42,25 @@ class FatSidebarItemOverlay: FatSidebarItem {
         self.trackingArea = newTrackingArea
     }
 
+    fileprivate func fireEnteredOrExitedWithInitialMouseCoordinates() {
+
+        guard let absoluteMousePoint = self.window?.mouseLocationOutsideOfEventStream else { return }
+
+        let mousePoint = self.convert(absoluteMousePoint, from: nil)
+
+        if NSPointInRect(mousePoint, self.bounds) {
+            mouseDidEnter()
+        } else {
+            mouseDidExit()
+        }
+    }
+
     override func mouseEntered(with event: NSEvent) {
+        mouseDidEnter()
+    }
+
+    /// - note: Use when event is not available, as in `updateTrackingRect`.
+    fileprivate func mouseDidEnter() {
 
         self.window?.disableCursorRects()
         NSCursor.pointingHand().set()
@@ -50,7 +77,13 @@ class FatSidebarItemOverlay: FatSidebarItem {
     }
 
     override func mouseExited(with event: NSEvent) {
+        mouseDidExit()
+    }
+
+    /// - note: Use when event is not available, as in `updateTrackingRect`.
+    fileprivate func mouseDidExit() {
 
+        didExit = true // Call before endHover to prevend updateTrackingRect loop
         endHover()
     }