Trying to replace the Gripper (which is a Label/Control) with adorners (custom code). This should prevent the slow cleanup, reduce resources and speedup the editor. Also we should have better "UI" feedback. This is still very experimental.

GreenshotPlugin/Interfaces/Drawing/Adorners/IAdorner.cs

@@ -0,0 +1,81 @@
+/*
+ * Greenshot - a free and open source screenshot tool
+ * Copyright (C) 2007-2015 Thomas Braun, Jens Klingen, Robin Krom
+ * 
+ * For more information see: http://getgreenshot.org/
+ * The Greenshot project is hosted on Sourceforge: http://sourceforge.net/projects/greenshot/
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 1 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Windows.Forms;
+
+namespace Greenshot.Plugin.Drawing.Adorners
+{
+	public interface IAdorner
+	{
+		/// <summary>
+		/// The owner of this adorner
+		/// </summary>
+		IDrawableContainer Owner { get; }
+
+		/// <summary>
+		/// Is the current point "over" the Adorner?
+		/// If this is the case, the 
+		/// </summary>
+		/// <param name="point">Point to test</param>
+		/// <returns>true if so</returns>
+		bool HitTest(Point point);
+
+		/// <summary>
+		/// Handle the MouseDown event
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="mouseEventArgs">MouseEventArgs</param>
+		void MouseDown(object sender, MouseEventArgs mouseEventArgs);
+
+		/// <summary>
+		/// Handle the MouseUp event
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="mouseEventArgs">MouseEventArgs</param>
+		void MouseUp(object sender, MouseEventArgs mouseEventArgs);
+
+		/// <summary>
+		/// Handle the MouseMove event
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="mouseEventArgs">MouseEventArgs</param>
+		void MouseMove(object sender, MouseEventArgs mouseEventArgs);
+
+		/// <summary>
+		/// Gets the cursor that should be displayed for this behavior.
+		/// </summary>
+		Cursor Cursor { get; }
+
+		/// <summary>
+		/// Draw the adorner
+		/// </summary>
+		/// <param name="paintEventArgs">PaintEventArgs</param>
+		void Paint(PaintEventArgs paintEventArgs);
+
+		/// <summary>
+		/// Called if the owner is transformed
+		/// </summary>
+		/// <param name="matrix">Matrix</param>
+		void Transform(Matrix matrix);
+	}
+}

GreenshotPlugin/Interfaces/Drawing/Container.cs

@@ -24,6 +24,8 @@ using System.Drawing.Drawing2D;
 using System.Drawing.Imaging;
 using System.Windows.Forms;
 using System.ComponentModel;
+using System.Collections.Generic;
+using Greenshot.Plugin.Drawing.Adorners;
 
 namespace Greenshot.Plugin.Drawing {
 	public enum RenderMode {EDIT, EXPORT};
@@ -73,7 +75,11 @@ namespace Greenshot.Plugin.Drawing {
 		Rectangle DrawingBounds {
 			get;
 		}
-		
+
+		void ApplyBounds(RectangleF newBounds);
+
+		void DoLayout();
+	
 		bool hasFilters {
 			get;
 		}
@@ -85,8 +91,6 @@ namespace Greenshot.Plugin.Drawing {
 		void AlignToParent(HorizontalAlignment horizontalAlignment, VerticalAlignment verticalAlignment);
 		void Invalidate();
 		bool ClickableAt(int x, int y);
-		void HideGrippers();
-		void ShowGrippers();
 		void MoveBy(int x, int y);
 		void Transform(Matrix matrix);
 		bool HandleMouseDown(int x, int y);
@@ -97,6 +101,11 @@ namespace Greenshot.Plugin.Drawing {
 		EditStatus DefaultEditMode {
 			get;
 		}
+
+		/// <summary>
+		/// Available adorners for the DrawableContainer
+		/// </summary>
+		IList<IAdorner> Adorners { get; }
 	}
 
 	public interface ITextContainer: IDrawableContainer {