Fix #593: Set progressBar.IsIndeterminate=false if the progress bar is invisible to avoid unnecessarily rendering at 60 FPS.

ILSpy/TextView/DecompilerTextView.cs

@@ -233,6 +233,9 @@ namespace ICSharpCode.ILSpy.TextView
 		{
 			if (waitAdorner.Visibility != Visibility.Visible) {
 				waitAdorner.Visibility = Visibility.Visible;
+				// Work around a WPF bug by setting IsIndeterminate only while the progress bar is visible.
+				// https://github.com/icsharpcode/ILSpy/issues/593
+				progressBar.IsIndeterminate = true;
 				waitAdorner.BeginAnimation(OpacityProperty, new DoubleAnimation(0, 1, new Duration(TimeSpan.FromSeconds(0.5)), FillBehavior.Stop));
 				var taskBar = MainWindow.Instance.TaskbarItemInfo;
 				if (taskBar != null) {
@@ -260,6 +263,7 @@ namespace ICSharpCode.ILSpy.TextView
 					if (currentCancellationTokenSource == myCancellationTokenSource) {
 						currentCancellationTokenSource = null;
 						waitAdorner.Visibility = Visibility.Collapsed;
+						progressBar.IsIndeterminate = false;
 						var taskBar = MainWindow.Instance.TaskbarItemInfo;
 						if (taskBar != null) {
 							taskBar.ProgressState = System.Windows.Shell.TaskbarItemProgressState.None;

ILSpy/TextView/DecompilerTextView.xaml

@@ -19,7 +19,7 @@
 				<Border Name="waitAdorner" Background="#C0FFFFFF" Visibility="Collapsed">
 					<StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
 						<TextBlock FontSize="14pt">Decompiling...</TextBlock>
-						<ProgressBar IsIndeterminate="True" Height="16" Margin="0, 4" />
+						<ProgressBar Name="progressBar" Height="16" Margin="0, 4" />
 						<Button Click="cancelButton_Click" HorizontalAlignment="Center">Cancel</Button>
 					</StackPanel>
 				</Border>