perf: prevent appkit work

src/ui/main-window/ThumbnailsPanel.swift

@@ -40,9 +40,12 @@ class ThumbnailsPanel: NSPanel {
             guard App.app.appIsBeingUsed else { return }
             NSScreen.preferred.repositionPanel(self)
         }
+        // prevent further AppKit work
+        thumbnailsView.clearNeedsLayout()
     }
 
     override func orderOut(_ sender: Any?) {
+        thumbnailsView.clearNeedsLayout()
         if Preferences.fadeOutAnimation {
             NSAnimationContext.runAnimationGroup(
                 { _ in animator().alphaValue = 0 },

src/ui/main-window/ThumbnailsView.swift

@@ -261,6 +261,15 @@ class ThumbnailsView {
         }
     }
 
+    func clearNeedsLayout() {
+        let views = [contentView, scrollView, scrollView.contentView, scrollView.documentView].compactMap { $0 }
+        for view in views {
+            view.needsLayout = false
+            view.needsDisplay = false
+            view.needsUpdateConstraints = false
+        }
+    }
+
     struct LayoutCache {
         var labelHeight = CGFloat(0)
         var iconWidth = CGFloat(0)