185: [Bug] Previews flicker when switching between clients with 'Hide previews when EVE client not active'

src/Eve-O-Preview/Configuration/Implementation/ThumbnailConfiguration.cs

@@ -32,9 +32,11 @@ namespace EveOPreview.Configuration.Implementation
 			this.HideActiveClientThumbnail = false;
 			this.MinimizeInactiveClients = false;
 			this.ShowThumbnailsAlwaysOnTop = true;
-			this.HideThumbnailsOnLostFocus = false;
 			this.EnablePerClientThumbnailLayouts = false;
 
+			this.HideThumbnailsOnLostFocus = false;
+			this.HideThumbnailsDelay = 2; // 2 thumbnails refresh cycles (1.0 sec)
+
 			this.ThumbnailSize = new Size(384, 216);
 			this.ThumbnailMinimumSize = new Size(192, 108);
 			this.ThumbnailMaximumSize = new Size(960, 540);
@@ -79,7 +81,6 @@ namespace EveOPreview.Configuration.Implementation
 		public bool HideActiveClientThumbnail { get; set; }
 		public bool MinimizeInactiveClients { get; set; }
 		public bool ShowThumbnailsAlwaysOnTop { get; set; }
-		public bool HideThumbnailsOnLostFocus { get; set; }
 
 		public bool EnablePerClientThumbnailLayouts
 		{
@@ -95,6 +96,9 @@ namespace EveOPreview.Configuration.Implementation
 			}
 		}
 
+		public bool HideThumbnailsOnLostFocus { get; set; }
+		public int HideThumbnailsDelay { get; set; }
+
 		public Size ThumbnailSize { get; set; }
 		public Size ThumbnailMaximumSize { get; set; }
 		public Size ThumbnailMinimumSize { get; set; }

src/Eve-O-Preview/Configuration/Interface/IThumbnailConfiguration.cs

@@ -16,9 +16,11 @@ namespace EveOPreview.Configuration
 		bool HideActiveClientThumbnail { get; set; }
 		bool MinimizeInactiveClients { get; set; }
 		bool ShowThumbnailsAlwaysOnTop { get; set; }
-		bool HideThumbnailsOnLostFocus { get; set; }
 		bool EnablePerClientThumbnailLayouts { get; set; }
 
+		bool HideThumbnailsOnLostFocus { get; set; }
+		int HideThumbnailsDelay { get; set; }
+
 		Size ThumbnailSize { get; set; }
 		Size ThumbnailMinimumSize { get; set; }
 		Size ThumbnailMaximumSize { get; set; }

src/Eve-O-Preview/Services/Implementation/ProcessMonitor.cs

@@ -8,15 +8,21 @@ namespace EveOPreview.Services.Implementation
 	{
 		#region Private constants
 		private const string DEFAULT_PROCESS_NAME = "ExeFile";
+		private const string CURRENT_PROCESS_NAME = "EVE-O Preview";
 		#endregion
 
 		#region Private fields
 		private readonly IDictionary<IntPtr, string> _processCache;
+		private IProcessInfo _currentProcessInfo;
 		#endregion
 
 		public ProcessMonitor()
 		{
 			this._processCache = new Dictionary<IntPtr, string>(512);
+			
+			// This field cannot be initialized properly in constructor
+			// At the moment this code is executed the main application window is not yet initialized
+			this._currentProcessInfo = new ProcessInfo(IntPtr.Zero, "");
 		}
 
 		private bool IsMonitoredProcess(string processName)
@@ -25,6 +31,41 @@ namespace EveOPreview.Services.Implementation
 			return String.Equals(processName, ProcessMonitor.DEFAULT_PROCESS_NAME, StringComparison.OrdinalIgnoreCase);
 		}
 
+		private IProcessInfo GetCurrentProcessInfo()
+		{
+			var currentProcess = Process.GetCurrentProcess();
+			return new ProcessInfo(currentProcess.MainWindowHandle, currentProcess.MainWindowTitle);
+		}
+
+		public IProcessInfo GetMainProcess()
+		{
+			if (this._currentProcessInfo.Handle == IntPtr.Zero)
+			{
+				var processInfo = this.GetCurrentProcessInfo();
+
+				// Are we initialized yet?
+				if (processInfo.Title != "")
+				{
+					this._currentProcessInfo = processInfo;
+				}
+			}
+
+			return this._currentProcessInfo;
+		}
+
+		public ICollection<IProcessInfo> GetAllProcesses()
+		{
+			ICollection<IProcessInfo> result = new List<IProcessInfo>(this._processCache.Count);
+
+			// TODO Lock list here just in case
+			foreach (KeyValuePair<IntPtr, string> entry in this._processCache)
+			{
+				result.Add(new ProcessInfo(entry.Key, entry.Value));
+			}
+
+			return result;
+		}
+
 		public void GetUpdatedProcesses(out ICollection<IProcessInfo> addedProcesses, out ICollection<IProcessInfo> updatedProcesses, out ICollection<IProcessInfo> removedProcesses)
 		{
 			addedProcesses = new List<IProcessInfo>(16);
@@ -76,18 +117,5 @@ namespace EveOPreview.Services.Implementation
 				this._processCache.Remove(index);
 			}
 		}
-
-		public ICollection<IProcessInfo> GetAllProcesses()
-		{
-			ICollection<IProcessInfo> result = new List<IProcessInfo>(this._processCache.Count);
-
-			// TODO Lock list here just in case
-			foreach (KeyValuePair<IntPtr, string> entry in this._processCache)
-			{
-				result.Add(new ProcessInfo(entry.Key, entry.Value));
-			}
-
-			return result;
-		}
 	}
 }

src/Eve-O-Preview/Services/Implementation/ThumbnailManager.cs

@@ -41,6 +41,7 @@ namespace EveOPreview.Services
 		private bool _isHoverEffectActive;
 
 		private int _refreshCycleCount;
+		private int _hideThumbnailsDelay;
 		#endregion
 
 		public ThumbnailManager(IMediator mediator, IThumbnailConfiguration configuration, IProcessMonitor processMonitor, IWindowManager windowManager, IThumbnailViewFactory factory)
@@ -66,6 +67,8 @@ namespace EveOPreview.Services
 			this._thumbnailUpdateTimer = new DispatcherTimer();
 			this._thumbnailUpdateTimer.Tick += ThumbnailUpdateTimerTick;
 			this._thumbnailUpdateTimer.Interval = new TimeSpan(0, 0, 0, 0, configuration.ThumbnailRefreshPeriod);
+
+			this._hideThumbnailsDelay = this._configuration.HideThumbnailsDelay;
 		}
 
 		public void Start()
@@ -180,10 +183,19 @@ namespace EveOPreview.Services
 		{
 			// TODO Split this method
 			IntPtr foregroundWindowHandle = this._windowManager.GetForegroundWindowHandle();
+
+			// The foreground window can be NULL in certain circumstances, such as when a window is losing activation.
+			// It is safer to just skip this refresh round than to do something while the system state is undefined
+			if (foregroundWindowHandle == IntPtr.Zero)
+			{
+				return;
+			}
+
 			string foregroundWindowTitle = null;
 
 			// Check if the foreground window handle is one of the known handles for client windows or their thumbnails
 			bool isClientWindow = this.IsClientWindowActive(foregroundWindowHandle);
+			bool isMainWindowActive = this.IsMainWindowActive(foregroundWindowHandle);
 
 			if (foregroundWindowHandle == this._activeClient.Handle)
 			{
@@ -195,14 +207,9 @@ namespace EveOPreview.Services
 				foregroundWindowTitle = foregroundView.Title;
 			}
 			else if (!isClientWindow)
-			{
-				// Under some circumstances Foreground WindowHandle can be zero
-				// (f.e. when Thumbnail is silently stealing focus from the currently open app)
-				if (foregroundWindowHandle != IntPtr.Zero)
 			{
 				this._externalApplication = foregroundWindowHandle;
 			}
-			}
 
 			// No need to minimize EVE clients when switching out to non-EVE window (like thumbnail)
 			if (!string.IsNullOrEmpty(foregroundWindowTitle))
@@ -210,7 +217,25 @@ namespace EveOPreview.Services
 				this.SwitchActiveClient(foregroundWindowHandle, foregroundWindowTitle);
 			}
 
-			bool hideAllThumbnails = this._configuration.HideThumbnailsOnLostFocus && !isClientWindow;
+			bool hideAllThumbnails = this._configuration.HideThumbnailsOnLostFocus && !(isClientWindow || isMainWindowActive);
+
+			// Wait for some time before hiding all previews
+			if (hideAllThumbnails)
+			{
+				this._hideThumbnailsDelay--;
+				if (this._hideThumbnailsDelay > 0)
+				{
+					hideAllThumbnails = false; // Postpone the 'hide all' operation
+				}
+				else
+				{
+					this._hideThumbnailsDelay = 0; // Stop the counter
+				}
+			}
+			else
+			{
+				this._hideThumbnailsDelay = this._configuration.HideThumbnailsDelay; // Reset the counter
+			}
 
 			this._refreshCycleCount++;
 
@@ -456,6 +481,7 @@ namespace EveOPreview.Services
 			this.EnqueueLocationChange(view);
 		}
 
+		// Checks whether currently active window belongs to an EVE client or its thumbnail
 		private bool IsClientWindowActive(IntPtr windowHandle)
 		{
 			if (windowHandle == IntPtr.Zero)
@@ -476,6 +502,12 @@ namespace EveOPreview.Services
 			return false;
 		}
 
+		// Check whether the currently active window belongs to EVE-O Preview itself
+		private bool IsMainWindowActive(IntPtr windowHandle)
+		{
+			return (this._processMonitor.GetMainProcess().Handle == windowHandle);
+		}
+
 		private void ThumbnailZoomIn(IThumbnailView view)
 		{
 			this.DisableViewEvents();

src/Eve-O-Preview/Services/Interface/IProcessMonitor.cs

@@ -4,6 +4,7 @@ namespace EveOPreview.Services
 {
 	public interface IProcessMonitor
 	{
+		IProcessInfo GetMainProcess();
 		ICollection<IProcessInfo> GetAllProcesses();
 		void GetUpdatedProcesses(out ICollection<IProcessInfo> addedProcesses, out ICollection<IProcessInfo> updatedProcesses, out ICollection<IProcessInfo> removedProcesses);
 	}