Disabled rerenders when background click is disabled (#436)

src/Blazored.Modal/BlazoredModalInstance.razor.cs

@@ -30,10 +30,22 @@ public partial class BlazoredModalInstance : IDisposable
     [SuppressMessage("Style", "IDE0044:Add readonly modifier", Justification = "This is assigned in Razor code and isn't currently picked up by the tooling.")]
     private ElementReference _modalReference;
     private bool _setFocus;
+    private bool _disableNextRender;
 
     // Temporarily add a tabindex of -1 to the close button so it doesn't get selected as the first element by activateFocusTrap
     private readonly Dictionary<string, object> _closeBtnAttributes = new() { { "tabindex", "-1" } };
 
+    protected override bool ShouldRender()
+    {
+        if (!_disableNextRender)
+        {
+            return true;
+        }
+
+        _disableNextRender = false;
+        return false;
+    }
+
     protected override void OnInitialized() 
         => ConfigureInstance();
 
@@ -313,7 +325,11 @@ private bool SetActivateFocusTrap()
 
     private async Task HandleBackgroundClick()
     {
-        if (DisableBackgroundCancel) return;
+        if (DisableBackgroundCancel)
+        {
+            _disableNextRender = true;
+            return;
+        }
 
         await CancelAsync();
     }