Make sure to check that previous/current window is valid.

Author: rxappdev

src/contents/ui/main.qml

@@ -854,15 +854,15 @@ Item {
                 }
             }
 
-            if (previousActiveWindow.resourceClass == clientName && validRestoredWindow != null && Workspace.activeWindow != validRestoredWindow) {
+            if (previousActiveWindow && previousActiveWindow.resourceClass == clientName && validRestoredWindow != null && Workspace.activeWindow != validRestoredWindow) {
                 if (previousActiveWindow != validRestoredWindow) {
                     log('Set active window - reason WINDOW DIFFERS!');
                     Workspace.activeWindow = validRestoredWindow;
                 } else {
                     log('Raise window - reason WINDOW DIFFERS!');
                     Workspace.raiseWindow(Workspace.activeWindow);
                 }
-            } else if (Workspace.activeWindow.resourceClass != clientName) {
+            } else if (Workspace.activeWindow && Workspace.activeWindow.resourceClass != clientName) {
                 log('Raise window - reason CLASS DIFFERS!');
                 Workspace.raiseWindow(previousActiveWindow);
             }

src/metadata.json

@@ -10,7 +10,7 @@
         "Description": "Save and restore application window positions (such as multi-window browsers)",
         "Icon": "preferences-desktop-virtual",
         "Id": "rememberwindowpositions",
-        "Version": "5.4.1",
+        "Version": "5.4.2",
         "License": "GPLv3",
         "Website": "https://github.com/rxappdev/RememberWindowPositions"
     },