Fix editor viewport activating while dragging a window

Source/Editor/GUI/Docking/WindowDragHelper.cs

@@ -32,9 +32,15 @@ namespace FlaxEditor.GUI.Docking
         /// The opacity of the dragged window when hint controls are shown.
         /// </summary>
         public const float DragWindowOpacity = 0.4f;
+        
+        /// <summary>
+        /// Returns true if any windows are being dragged.
+        /// </summary>
+        public static bool IsDragActive { get; private set; }
 
         private WindowDragHelper(FloatWindowDockPanel toMove, Window dragSourceWindow)
         {
+            IsDragActive = true;
             _toMove = toMove;
             _toSet = DockState.Float;
             var window = toMove.Window.Window;
@@ -72,6 +78,7 @@ namespace FlaxEditor.GUI.Docking
         /// </summary>
         public void Dispose()
         {
+            IsDragActive = false;
             var window = _toMove?.Window?.Window;
 
             // Unbind events

Source/Editor/Viewport/EditorViewport.cs

@@ -4,6 +4,7 @@ using System;
 using System.Linq;
 using FlaxEditor.Content.Settings;
 using FlaxEditor.GUI.ContextMenu;
+using FlaxEditor.GUI.Docking;
 using FlaxEditor.GUI.Input;
 using FlaxEditor.Options;
 using FlaxEditor.Viewport.Cameras;
@@ -1578,7 +1579,7 @@ namespace FlaxEditor.Viewport
 
             // Update input
             var window = win.Window;
-            var canUseInput = window != null && window.IsFocused && window.IsForegroundWindow;
+            var canUseInput = window != null && window.IsFocused && window.IsForegroundWindow && !WindowDragHelper.IsDragActive;
             {
                 // Get input buttons and keys (skip if viewport has no focus or mouse is over a child control)
                 var isViewportControllingMouse = canUseInput && IsControllingMouse;