Improve documents

Author: Jack251970

Flow.Launcher.Plugin/IProgressBoxEx.cs

@@ -6,15 +6,15 @@
 public interface IProgressBoxEx
 {
     /// <summary>
-    /// Show progress box
+    /// Show progress box. It should be called from the main ui thread.
     /// </summary>
     /// <param name="progress">
     /// Progress value. Should be between 0 and 100. When progress is 100, the progress box will be closed.
     /// </param>
     public void ReportProgress(double progress);
 
     /// <summary>
-    /// Close progress box.
+    /// Close progress box. It should be called from the main ui thread.
     /// </summary>
     public void Close();
 }