Squashed commit of the following:

commit 9a17c62ecbafdac7084c862058c8ade4a8102406
Author: Collider LI <lhc199652@gmail.com>
Date:   Sat Apr 23 22:48:46 2022 -0400

    Make the fix #3399 macOS 11 only

commit b01feb81858c1c9dc3af273012f75cc5e25c0f45
Merge: d5e4300 51b5a22
Author: Collider LI <lhc199652@gmail.com>
Date:   Sat Apr 23 22:30:29 2022 -0400

    Merge branch 'fix-3364' of https://github.com/xjbeta/iina-danmaku into xjbeta-fix-3364

commit 51b5a22
Author: xjbeta <xjbeta.tiny@gmail.com>
Date:   Mon Apr 26 23:48:53 2021 +0800

    Fix #3364.

iina/MainWindowController.swift

@@ -9,6 +9,16 @@
 import Cocoa
 import Mustache
 
+fileprivate let isMacOS11: Bool = {
+  var res = false
+  if #available(macOS 11.0, *) {
+    if #available(macOS 12.0, *) {} else {
+      res = true
+    }
+  }
+  return res
+}()
+
 fileprivate let TitleBarHeightNormal: CGFloat = {
   if #available(macOS 10.16, *) {
     return 28
@@ -702,9 +712,14 @@ class MainWindowController: PlayerWindowController {
       oscFloatingTopView.addView(fragVolumeView, in: .leading)
       oscFloatingTopView.addView(fragToolbarView, in: .trailing)
       oscFloatingTopView.addView(fragControlView, in: .center)
-      oscFloatingTopView.setVisibilityPriority(.detachOnlyIfNecessary, for: fragVolumeView)
-      oscFloatingTopView.setVisibilityPriority(.detachOnlyIfNecessary, for: fragToolbarView)
-      oscFloatingTopView.setClippingResistancePriority(.defaultLow, for: .horizontal)
+
+      // Setting the visibility priority to detach only will cause freeze when resizing the window
+      // (and triggering the detach) in macOS 11.
+      if !isMacOS11 {
+        oscFloatingTopView.setVisibilityPriority(.detachOnlyIfNecessary, for: fragVolumeView)
+        oscFloatingTopView.setVisibilityPriority(.detachOnlyIfNecessary, for: fragToolbarView)
+        oscFloatingTopView.setClippingResistancePriority(.defaultLow, for: .horizontal)
+      }
       oscFloatingBottomView.addSubview(fragSliderView)
       Utility.quickConstraints(["H:|[v]|", "V:|[v]|"], ["v": fragSliderView])
       Utility.quickConstraints(["H:|-(>=0)-[v]-(>=0)-|"], ["v": fragControlView])
@@ -1425,6 +1440,36 @@ class MainWindowController: PlayerWindowController {
       controlBarFloating.xConstraint.constant = xPos
       controlBarFloating.yConstraint.constant = yPos
     }
+
+    // Detach the views in oscFloatingTopView manually on macOS 11 only; as it will cause freeze
+    if isMacOS11 && oscPosition == .floating {
+      guard let maxWidth = [fragVolumeView, fragToolbarView].compactMap({ $0?.frame.width }).max() else {
+        return
+      }
+
+      // window - 10 - controlBarFloating
+      // controlBarFloating - 12 - oscFloatingTopView
+      let margin: CGFloat = (10 + 12) * 2
+      let hide = (window.frame.width
+                    - fragControlView.frame.width
+                    - maxWidth*2
+                    - margin) < 0
+
+      let views = oscFloatingTopView.views
+      if hide {
+        if views.contains(fragVolumeView)
+            && views.contains(fragToolbarView) {
+          oscFloatingTopView.removeView(fragVolumeView)
+          oscFloatingTopView.removeView(fragToolbarView)
+        }
+      } else {
+        if !views.contains(fragVolumeView)
+            && !views.contains(fragToolbarView) {
+          oscFloatingTopView.addView(fragVolumeView, in: .leading)
+          oscFloatingTopView.addView(fragToolbarView, in: .trailing)
+        }
+      }
+    }
   }
 
   // resize framebuffer in videoView after resizing.