remove Topmost="True" and add Gremlin.ico

Gremlin/GUI/ChooseDB.xaml

@@ -7,7 +7,6 @@
         Title="ChooseDB" Height="309" Width="600" 
         WindowStyle="None"
         ResizeMode="NoResize"
-        Topmost="True" 
         WindowStartupLocation="CenterScreen" 
         SizeToContent="Height" 
         ShowInTaskbar="False">

Gremlin/GUI/Login.xaml

@@ -7,6 +7,7 @@
         Title="Gremlin Login" Height="130" Width="350"
         WindowStyle="None"
         ResizeMode="NoResize"
+        SizeToContent="Height" 
         WindowStartupLocation="CenterScreen">
     <Grid>
         <Grid.RowDefinitions>

Gremlin/GUI/Login.xaml.cs

@@ -27,8 +27,8 @@ namespace Gremlin.GUI
                 _ = MessageBox.Show("Login Name oder Passwort falsch!", "Login failed!", MessageBoxButton.OK, MessageBoxImage.Error);
             }
             MainWindow mainWindow = new();
-            mainWindow.Show();
             Close();
+            mainWindow.Show();
         }
     }
 }

Gremlin/GUI/MainWindow.xaml

@@ -6,6 +6,7 @@
         mc:Ignorable="d"
         Title="Gremlin" Height="850" Width="1200"
         ResizeMode="NoResize"
+        WindowStyle="SingleBorderWindow"
         WindowStartupLocation="CenterScreen" >
     <Grid Width="1189">
         <Grid.RowDefinitions>

Gremlin/Gremlin.csproj

@@ -10,6 +10,7 @@
     <RepositoryUrl>https://github.com/Basimodo/Gremlin</RepositoryUrl>
     <RepositoryType>GitHub</RepositoryType>
     <Copyright>2021</Copyright>
+    <ApplicationIcon>gremlin.ico</ApplicationIcon>
   </PropertyGroup>
 
   <ItemGroup>