Crash in Vulkan RHI if window is recreated (released its resources on hide) (Qt 5.15)

We have some custom QML comboboxes that use QML Window for the popovers.

To conserve GPU memory after they are initialized, we call on them:

// Release SceneGraph when hiding window
window->setPersistentSceneGraph( false );
// Release RHI (and GPU memory) if SG being release above too
window->setPersistentOpenGLContext( false ); 

This triggers a crash if window is reopened (recreated). For some reason the crash only occurs if the window width changes on the reopen. The general cause of the crash is:

1. new frame has been started (primary VkCommand has been created)
2. frame has been interrupted with a call to releaseSwapChainResources()
3. the above call destroys the primary VkCommands
4. but left the inFrame flag untouched
5. next call to beginFrame() was not recreating the VkCommand as it assumed that it just needs to continue work on the prevously abandoned one
6. crash due to use of nullptr VkCommand

My fix:

@@ -1500,12 +1500,14 @@ void QRhiVulkan::releaseSwapChainResources(QRhiSwapChain *swapChain)
     if (swapChainD->sc == VK_NULL_HANDLE)
         return;
 
     if (!deviceLost)
         df->vkDeviceWaitIdle(dev);
 
+    inFrame = false;
+
     for (int i = 0; i < QVK_FRAMES_IN_FLIGHT; ++i) {