fix: don't display invalid windows (may fix #292 #200)

src/logic/Windows.swift

@@ -94,6 +94,12 @@ class Windows {
         }
     }
 
+    // some window can get invalid *after* we add them to our list, but without us getting notified about it
+    // workaround: we remove the invalid windows right before showing the UI
+    static func removeWindowsWhichBecameInvalid() {
+        Windows.list.removeAll(where: { !$0.axUiElement.isActualWindow($0.application.runningApplication.bundleIdentifier) })
+    }
+
     static func refreshIfWindowShouldBeShownToTheUser(_ window: Window, _ screen: NSScreen) {
         window.shouldShowTheUser = !(!Preferences.showMinimizedWindows && window.isMinimized) &&
             !(!Preferences.showHiddenWindows && window.isHidden) &&

src/ui/App.swift

@@ -194,6 +194,7 @@ class App: NSApplication, NSApplicationDelegate {
             // TODO: find a way to update space index when windows are moved to another space, instead of on every trigger
             Windows.updateSpaces()
             let screen = Screen.preferred()
+            Windows.removeWindowsWhichBecameInvalid()
             Windows.refreshWhichWindowsToShowTheUser(screen)
             if Windows.list.first(where: { $0.shouldShowTheUser }) == nil { hideUi(); return }
             Windows.updateFocusedWindowIndex(0)