Add cursor to change to Ibeam in text boxes.

Source/Engine/UI/GUI/Common/TextBoxBase.cs

@@ -1128,6 +1128,23 @@ namespace FlaxEngine.GUI
             base.OnSubmit();
         }
 
+        /// <inheritdoc />
+        public override void OnMouseEnter(Float2 location)
+        {
+            Cursor = CursorType.IBeam;
+            base.OnMouseEnter(location);
+        }
+
+        /// <inheritdoc />
+        public override void OnMouseLeave()
+        {
+            if (Cursor == CursorType.IBeam)
+            {
+                Cursor = CursorType.Default;
+            }
+            base.OnMouseLeave();
+        }
+
         /// <inheritdoc />
         public override void OnMouseMove(Float2 location)
         {
@@ -1141,6 +1158,11 @@ namespace FlaxEngine.GUI
                 // Modify selection end
                 SetSelection(_selectionStart, currentIndex);
             }
+            
+            if (Cursor == CursorType.Default)
+            {
+                Cursor = CursorType.IBeam;
+            }
         }
 
         /// <inheritdoc />
@@ -1169,6 +1191,11 @@ namespace FlaxEngine.GUI
                 {
                     SetSelection(hitPos);
                 }
+                
+                if (Cursor == CursorType.Default)
+                {
+                    Cursor = CursorType.IBeam;
+                }
 
                 return true;
             }