fix issues when returning to the MainPage

Author: Trolldemorted

Signal-Windows/ViewModels/MainPageViewModel.cs

@@ -150,6 +150,16 @@ internal async Task SendMessageButton_Click(TextBox messageTextBox)
             messageTextBox.Focus(FocusState.Programmatic);
         }
 
+        internal void Deselect()
+        {
+            if (SelectedConversation != null)
+            {
+                RequestedConversationId = SelectedConversation.ThreadId;
+            }
+            SelectedConversation = null;
+            SelectedThread = null;
+        }
+
         public void TrySelectConversation(string conversationId)
         {
             if (conversationId != null && ConversationsDictionary.ContainsKey(conversationId))

Signal-Windows/Views/MainPage.xaml.cs

@@ -81,7 +81,10 @@ public PageStyle GetCurrentViewStyle()
 
         protected override void OnNavigatedTo(NavigationEventArgs e)
         {
-            Vm.RequestedConversationId = e.Parameter as string;
+            if (e.Parameter != null)
+            {
+                Vm.RequestedConversationId = e.Parameter as string;
+            }
             UpdateLayout();
             SwitchToStyle(GetCurrentViewStyle());
             MainPanel.DisplayMode = SplitViewDisplayMode.CompactInline;
@@ -91,6 +94,7 @@ protected override void OnNavigatedTo(NavigationEventArgs e)
 
         protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
         {
+            Vm.Deselect();
             Frame.SizeChanged -= Frame_SizeChanged;
             if (GetCurrentViewStyle() == PageStyle.Narrow)
             {