diff --git a/src/Avalonia.Controls/Control.cs b/src/Avalonia.Controls/Control.cs
index fa0d8fe7d6..27b046cf47 100644
--- a/src/Avalonia.Controls/Control.cs
+++ b/src/Avalonia.Controls/Control.cs
@@ -645,7 +645,7 @@ namespace Avalonia.Controls
 
             if (_focusAdorner != null)
             {
-                var adornerLayer = (Panel)_focusAdorner.Parent;
+                var adornerLayer = (IPanel)_focusAdorner.Parent;
                 adornerLayer.Children.Remove(_focusAdorner);
                 _focusAdorner = null;
             }
diff --git a/src/Avalonia.Controls/TopLevel.cs b/src/Avalonia.Controls/TopLevel.cs
index 7e0f4b7ac1..567ca80d6e 100644
--- a/src/Avalonia.Controls/TopLevel.cs
+++ b/src/Avalonia.Controls/TopLevel.cs
@@ -189,7 +189,7 @@ namespace Avalonia.Controls
         protected virtual IRenderTarget CreateRenderTarget()
         {
             if(PlatformImpl == null)
-                throw new InvalidOperationException("PlatformImpl isn't available");
+                throw new InvalidOperationException("Cann't create render target, PlatformImpl is null (might be already disposed)");
             return _renderInterface.CreateRenderTarget(PlatformImpl.Surfaces);
         }
 
diff --git a/src/Avalonia.DotNetFrameworkRuntime/AppBuilder.cs b/src/Avalonia.DotNetFrameworkRuntime/AppBuilder.cs
index f8e8d4b094..9a54cdbab0 100644
--- a/src/Avalonia.DotNetFrameworkRuntime/AppBuilder.cs
+++ b/src/Avalonia.DotNetFrameworkRuntime/AppBuilder.cs
@@ -83,7 +83,7 @@ namespace Avalonia
         private void LoadAssembliesInDirectory()
         {
             var location = Assembly.GetEntryAssembly().Location;
-            if(location == null)
+            if (string.IsNullOrWhiteSpace(location))
                 return;
             var dir = new FileInfo(location).Directory;
             if (dir == null)